The Science of Hearing, Balance & Accelerated Learning

welcome to the huberman lab podcast where we discuss science and science-based tools for everyday life i'm andrew hueberman and i'm a professor of neurobiology and ophthalmology at stanford school of medicine today we're going to talk all about hearing and balance and how you can use your ability to hear specific things and your balance system in order to learn anything faster the auditory system meaning the hearing system and your balance system which is called the vestibular system interact with all the other systems of the brain and body and used properly can allow you to learn information more quickly remember that information longer and with more ease and you can also improve the way you can hear you can improve your balance we're going to talk about tools for all of that this is one area of science where we understand a lot about the cells and the mechanisms in the ear and in the brain and so forth so we're going to talk about that a little bit and then we're going to get directly into protocols meaning tools we're also going to talk about ways in which the auditory imbalance system suffer we're going to talk about tinnitus which is this ringing of the years that unfortunately for people that suffer from it they really suffer it's very intrusive for them we're going to talk about some treatments that can work in some circumstances and some of the more recent emerging treatments that i think many people aren't aware of we're also going to talk about this what seems like kind of a weird fact which is that 70 percent of people all people make what are called auto acoustic emissions their ears actually make noises chances are you your ears are making noises right now but you can't perceive them and yet those can have an influence on other people and animals in your environment it's a fascinating aspect to your biology you're going to learn a lot about how your biology and brain and ears and the so-called inner ear that's associated with balance you're going to learn a lot about how all those work you're going to learn a lot of neuroscience i'll even tell you what type of music to listen to and if you listen to me you can leverage that in order to learn faster before we begin talking about the science of hearing and balance and tools that leverage hearing imbalance for learning faster i want to provide some information about another way to learn much faster there's a paper that was published recently this is a paper that was published in cell reports an excellent journal it's a peer-reviewed paper from a really excellent group looking at skill learning now previously i've talked about how in the attempt to learn skills the vital thing to do is to get lots of repetitions you've heard of the 10 000 hours thing you've heard of you know lots of different strategies for learning faster 80 20 rule and all that the bottom line is you need to generate many many repetitions of something that you're trying to learn and the errors that you generate are also very important for learning it also turns out that taking rest within the learning episode is very important i want to be really clear what i'm referring to here in earlier episodes i've discussed how when you're trying to learn something it's beneficial it's been shown in scientific studies that if you take a 20-minute shallow nap or you simply do nothing after a period of learning that it enhances the rates of learning and the depth of learning your ability to learn and remember that information what i'm about to describe are new data that say that you actually should be should be injecting rest within the learning episode i'm not talking about going to sleep while learning this is the way that the study was done the study involved having people learn sequences of numbers or keys on a piano so let's use the keys on a piano example i'm not a musician but i think i'll get this correct they asked people to practice a sequence of keys g d f e g g d f e g g d f e g and they would practice that either continually for a given amount of time or they would just do that for 10 seconds they would play g d f e g g d f e g g d f e g g d f e g for 10 seconds and then they would take a 10 second pause a rest it would just space take a space or a period of time but they do nothing for 10 seconds then they would go back to g d f e g g d f e g so the two conditions essentially were to have people practice continually lots of repetitions or to inject or insert these periods of of 10 seconds idle time where they're not doing anything they're not looking at their phone they're not focusing on anything they're just letting their mind drift wherever it wants to go and they are not touching the keys on the keyboard what they found was that the rates of learning the skill acquisition and the retention of the skills was significantly faster when they injected these short periods of rest these 10-second rest periods and the the rates of learning were when i say significantly faster were much much faster i'll reveal what that was in just a moment but you might ask why would this work why would it be that injecting these 10 second rest periods would enhance rates of learning what they called them was micro offline gains because they're sort of taking their brain offline from the learning task for a moment well it turns out the brain isn't going offline at all you've probably heard of the hippocampus the area of the brain involved in memory and the neocortex the area of the brain that's involved in processing sensory information well it turns out that during these brief periods of rest these 10 second rest periods the hippocampus and the cortex are active in ways such that you get a 20 times repeat of the gd feg it's a temporal compression as they say so basically the rehearsal continues while you rest but at 20 times the speed so if you were normally getting just let's just say five repetitions of gdf eg gdfeg gdfeg per 10 seconds now you multiply that times 20 in the rest periods you've practiced it 100 times your brain has practiced it we know this because they were doing brain imaging functional imaging of these people with brain scanners while they were doing this this is an absolutely staggering effect and it's one that believe it or not has been hypothesized or thought to exist for a very long time this effect is called the spacing effect and it was actually first proposed by ebington in 1885 and since then it's been demonstrated for a huge number of different what they call domains in the cognitive domain so for learning languages for in the physical domain so for learning skills that involve a motor sequence it's been demonstrated for a huge number of different categories of learning if you want to learn all about the spacing effect and the categories of learning that it can impact there's a wonderful review article i'll provide a link to it the title of the review article is parallels between spacing effects during behavioral and cellular learning what that review really does is it ties the behavioral learning and the improvement of skill to the underlying changes in neurons that can explain that learning i should mention that the paper that i'm referring to the more recent paper that injects these 10 second little micro offline games rest periods is the work of the laboratory of leonard cohen not the musician letter and cohen he passed away he was not a neuroscientist a wonderful poet a musician but not a neuroscientist again the paper was published in cell reports and we will provide a link to the full paper as well so the takeaway is if you're trying to learn something you need to get those reps in but one way that you can get 20 times the number of reps in is by injecting these little 10 second periods of doing nothing again during those rest periods you really don't want to attend to anything else as much as possible you could close your eyes if you want or you can just simply wait and then get right back into generating repetitions i find these papers that sell reports and other journals have been publishing recently to be fascinating because they're really helping us understand what are the best protocols for learning anything and they really uh leverage the fact that the brain is willing to generate repetitions for us provide provided that we give it the rest that it needs so inject rest throughout the learning period and if you can based on the scientific data you would also want to take a 20 minute nap or a 20 minute decompress period where you're not doing anything after a period of learning i think those could both synergize in order to enhance learning even further although that hasn't been looked at yet before we begin talking about hearing and balance i just want to mention that this podcast is separate from my teaching and research roles at stanford it is however part of my desire and effort to bring zero cost to consumer information about science and science related tools to the general public in keeping with that theme i want to thank the sponsors of today's podcast and make it clear that we only work with sponsors whose products we absolutely love and that we think you will benefit from as well our first sponsor is roka roka makes sunglasses and eyeglasses that in my opinion are the very highest quality available the company was founded by two all-american swimmers from stanford and everything about their eyeglasses and sunglasses were created with performance in mind these eyeglasses and sunglasses have a number of features that really make them unique first of all they're extremely lightweight the optical clarity of the lenses is spectacular and for the sunglasses they have this really great feature which is as you move in and out of shadows or as across the day the amount of sunshine might change you always experience the world as clear and bright and that can only come from really understanding how the visual system works the visual system has all 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levels of hormone factors metabolic factors etc but the dashboard inside tracker provides directives so that if you want to bring those numbers up or bring them down or if you want to keep them in the same range it points to specific regimens related to nutrition exercise and other lifestyle factors so you can really move around those numbers to best suit your health goals and health status if you want to try inside tracker you can go to insidetracker.com huberman and you'll get 25 percent off any of inside tracker's plans just use the code huberman at checkout today's podcast is also brought to us by headspace headspace is a meditation app that's backed by 25 published studies and in addition to those there are hundreds of studies showing that meditation is beneficial for our brain and for our body one of the challenges however is maintaining a meditation practice i started meditating a long time ago but i found it very hard to keep that practice going then i discovered the headspace meditation app and what i found was that because they have meditations that are very short as well as some that are longer and some that are much longer i could maintain my meditation practice sometimes i do a short five-minute meditation sometimes i do 20-minute meditation i try and meditate at least 20 minutes per day but sometimes some weeks i only do it five times a week and i'll just meditate for longer so with headspace you have the full palette of meditations to select from if you want to try headspace you can go to headspace.com special offer and if you do that you'll get a free one-month trial so no cost whatsoever with their full library of meditations that's the best offer that they have so again if you want to try headspace and you want to get access to all their meditations for free go to headspace.com special offer can you hear me can you hear me okay well if you can hear me that's amazing because what it means is that my voice is causing little tiny changes in the airwaves wherever you happen to be and that your ears and whatever is contained in those ears and in your brain can take those sound waves and make sense of them and that is an absolutely fantastic and staggering feat of biology and yet we understand a lot about how that process works so i'm going to teach it to you now in simple terms over the next few minutes so what we call ears have a technical name that technical technical name is oracles but more often they're called pinna the pinas p-i-n-n-a pinna and the pinnas of your ears this outer part that is made of cartilage and stuff is arranged such that it can capture sound in the best way for your head size we're going to talk about ear size also because it turns out that your ears change size across the lifespan and that how big your ears are or rather how fast your ears are changing size is a pretty good indication of how fast you're aging so we'll get to that in a few minutes but i want to talk about these things that we call ears and some of the stuff contained within them that allow us to hear so the shape of these ears that we have is such that it amplifies high frequency sounds high frequency sounds as the name suggests so that is the squeakier stuff right so low frequency sound cost yellow snoring in the background that's a low frequency sound or high frequency sound okay so we have low frequency sounds and high frequency sounds and everything in between now those sound waves get captured by our ears and those sound waves for those of you that don't maybe fully conceptualize sound waves are literally just fluctuations or shifts in the way that air is moving toward your ear and through space in the same way that water can have waves the air can have waves okay so it's reverberation of air those come in through your ears and you have what's called your eardrum and on the inside of your eardrum there's a little bony thing that's shaped like a little hammer so attached to that eardrum which can move back and forth like a drum it's like a little membrane you've got this hammer attached to it and that hammer has three parts for those of you that want to know those three parts are called malleus incus and stapes it's like but basically just think about it as a hammer so you've got this eardrum and then a hammer and then that hammer has to hammer on something and what it does is it hammers on a little coiled piece of tissue that we call the cochlea sometimes called the cochlea depending on where somebody lives in the country so typically in the midwest on the east coast they call them cochlea and on the west coast we call them cochlea same thing okay so this snail-shaped structure in your inner ear is where sound gets converted into electrical signals that the brain can understand but i want to just bring your attention to that little hammer because that little hammer is really really cool what it means is that sound waves come in through your ears that's what's happening right now that eardrum that you have is like a it's like the top of a drum it's like a membrane or it can move back and forth it's not super rigid and it moves that little hammer and then the hammer goes and hits this coil shaped thing that we're calling the cochlea okay now the cochlea at one end is more rigid than the other so one part can move really easily and the other part doesn't move very easily and that turns out to be very important for decoding or separating sounds that are low frequency like costello's snoring and sounds that are of high frequency like a shriek or a shrill and that's because within that little coiled thing we call the cochlea you have all these tiny little what are called hair cells now they look like hairs but they're not at all related to the hairs on your head or elsewhere on your body they're just shaped like hair so we call them hair cells those hair cells if they move send signals into the brain that a particular sound is in our environment and if those hair cells don't move it means that particular sound is not in our environment okay so just to give you the mental picture of this sound waves are coming in because there's stuff out there making noises like my voice it's changing the patterns of air around you in very very subtle ways that information is getting funneled into your ears because your pinnas are shaped in a particular way the eardrum then moves this little hammer and the hammer bangs on this little snail shaped thing and because that snail shaped thing at one end is very rigid it doesn't want to move and at the other end it's very flexible it can separate out high frequency and low frequency sounds and the fact that this thing in your inner ear that we call the cochlea is coiled is actually really important to understand because along its length it varies in how rigid or flexible it is i already mentioned that before and at the base it's very rigid and that's where the hair cells if they move will make high frequency sounds and at the top what's called the apex it's very flexible and it's more like a bass drum so basically what happens is sound waves come into your ears and then at one end of this thing that we call the cochlea at the top it's essentially encoding or only responding to sounds are like whereas at the bottom it responds to high frequency sounds like a symbol okay and everywhere in between we have other frequencies medium frequencies now this should stagger your mind if it doesn't already it should because what this means is that everything that's happening around us whether or not it's music or voices or crying or screaming or screaming of delight from small children who are excited because they're playing or because they get cake all of that is being broken down into its component parts and then your brain is making sense of what it means these things that i've been talking about like the pin of your ears and this little hammer and the cochlea that's all purely mechanical it has no mind of its own it's just breaking things down into high frequencies medium frequencies and low frequencies and if you don't understand sound frequency it's really simple to understand just imagine ripples on a pond and if those ripples are very close together that's high frequency they occur at high frequency if those ripples are further apart it's low frequency and obviously medium frequency is in between so just like you can have waves in water you can have waves in air so that's that's really how it works now we're all we are all familiar with light and how if you take a prism and put it in front of light it will split that light into its different wavelengths it's different colors red green blue etc right sort of like the pink floyd dark side of the moon album i think has a prism and it's converting white light into all the colors all the wavelengths that are contained in white light your cochlea essentially acts as a prism it takes all the sound in your environment and it splits up those sounds into different frequencies so you can think of the cochlea of your ear sort of like a prism and then the brain takes that information and puts it back together and makes sense of it so those hair cells in each of your two cochlea because you have two ears you also have two cochlea send little wires what we call axons that convey their patterns of activity into the brain and there are a number of different stations within the brain that information arrives at before it gets up to the parts of your brain where you are consciously aware and because some of you have asked for more names and nomenclature i'll give that to you if you don't want a lot of detailed names you can just ignore what i'm about to say but basically the cochlea send information to what's called the spiral ganglion the spiral gang a ganglion by the way if you're going to learn any neuroscience just know that anytime you hear ganglion a ganglion is just a clump so it means a bunch of neurons so a clump of cells so the spiral ganglion is a bunch of neurons that the information then goes off to what are called the cochlear nuclei in the brain stem brain stem is kind of down near your neck then up to a structure that has a really cool name called the superior olive because it uh you have one on each side of your brain um and if i were to bring you to my lab and show you the superior olives in your brain or anyone else's brain they look like little olives they even have a little divot in them that to me looks like a pimiento but they just called them the super the superior olive and then the the neurons in the superior olive then they send information up to what's called the inferior colliculus only called inferior because it sits below a structure called the superior colliculus and then the information goes up to what's called the medial geniculate nucleus and then up to your neocortex where you make sense of it all now you don't have to remember all that but you should know that there are a lot of stations in which auditory information is processed before it gets up to our conscious detection and there is a good reason for that which is that more important than knowing what you're hearing you need to know where it's coming from it's vital to our survival that if something for instance is falling toward us that we know if it's coming to our right side if it's going to hit us from behind we have to know for instance if a car is is coming at us from our left or from our right and our visual system can help with that but our auditory and our visual system collaborate to help us find and locate the position of things in space that should come as no surprise if you hear somebody talking off to your right you tend to turn to your right not to your left if you see somebody's mouth moving in front of you you tend to assume that the sound is going to come from right in front of you disruptions in this auditory hearing and visual matching are actually the basis of what's called the ventriloquism effect which we'll talk about in a few minutes in more depth but the ventriloquism effect can basically be described in simple terms as when you essentially think that a sound is coming from a location that it's not actually coming from we'll talk about that in a moment but what i'd like you to realize is that one of these stations deep in your brain stem is responsible for helping you identify where sounds are coming from through a process that's called inter-oral time differences and that sounds fancy but really the way you know where things are coming from what direction a car or a boss or a person is coming from is because the sound lands in one ear before the other and you have stations in your brain and you meaning you have neurons in your brain that calculate the difference in time of arrival for those sound waves in your right versus your left ear and if they arrive at the same time you assume that thing is making noise right in front of you if it's off to your right you assume it's over on your right and if the sound arrives first to your left ear you assume quite correctly that the thing is coming toward your left ear so it's a very simple and kind of a mechanical system at the level of sound localization but what about up and down if you think about it a sound coming from above is going to land on your right ear and your left ear at the same time a sound from below is going to land on your right ear and your left ear at the same time so the way that we know where things are in terms of what's called elevation where they are in the up and down plane is by the frequencies the shape of your ears actually modifies the sound depending on whether or not it's coming straight at you from the floor or from high above and so already at the level of your ears you are taking information about the outside world and determining where that information is coming from now this all happens very very fast in subconscious but now you know why if people really want to hear something they make a cup around their ear they essentially make their ear into more of a fennec fox type ear if you've ever seen those cute little fennec fox things they have these big spiky ears they kind of look like a french bulldog although they're kind of the fox version version of the french bulldog these big big tall ears and they have excellent sound localization and so when people lean in with their you're like with their hand like this if you're listening to this i'm just cupping my hand at my ear i'm giving myself a bigger pinna okay and if i do it on the left side i do this side and if i really want to hear something i do it on both sides okay so this isn't just gesturing this actually serves a mechanical role and actually if you want to hear where things are coming from with a much greater degree of accuracy this can actually help because you're capturing sound waves and funneling them better it's really remarkable this whole system so you've got these two ears and because of the differences in the timing of when things arrive in those two years as well as these differences in the frequencies of that certain things sound or i should say the differences in the frequencies that arrive at your ears depending on whether or not the thing is above you or right in front of you or below you you're able to make out where things are in space pretty well so now you're probably starting to realize that these two things on the side of our head that we call ears are there for a lot more than hanging earrings on or for other aesthetic purposes or for putting sunglasses on top of they are very powerful devices for allowing us to capture sound waves from our environment now i have a question for you which is can you move your ears turns out that unlike other animals humans are not terrifically good at moving their ears other animals can move their ears even independently so costello is pretty good at raising his ears the two of them together he can't really move his ears separately some dogs can do that really well in fact sight hounds and some scent hounds do that exquisitely well some animals like deer and other animals that really have a very acute hearing will put one ear down to a very particular angle and will tilt the other one and they will actually capture information about two distant sound making organisms those could be hunters coming after them or other animals coming after them they are very good at doing this we're not so good at it but about 60 percent of people it's thought can move their ears consciously without having to touch their ears so can you do that maybe you should try it ask someone to look at you and see whether or not you can do it the typical distances that people can move it is usually no more than two or three millimeters it's subtle but can you flap your pinna with uh just using mental control if you can or if you can't try looking all the way to your right or all the way to your left if obviously if you're driving a car or doing something or exercising don't put yourself in danger right now but if you move your eyes all the way to your left which i'm doing now or all the way to my right you might feel a little bit of a contraction of the muscles it's a that control ear movement all right now i want to ask you this can you raise one eyebrow i'm not very good at i can do a little bit but it's mostly by like cramping down my face on one side and i certainly can't raise my right eyebrow i can only do my like left eyebrow trying to talk while i'm doing this so that's why it looks strange people who can raise one eyebrow very easily almost always can move their ears without having to touch them it's controlled by the same motor pathway and there does seem to be a small but statistically significant sex difference in the ability to move one's ears typically men can do this more than women can although plenty of women can move their ears as well now if you think that is all a little strange or off topic it's not because what we're really talking about here is a system of the brain but also of the body of the musculature for localizing things in space and so it you might find it interesting to note that one of the things that we share very closely with other primates with non-human primates like macaque monkeys and chimpanzees if you look at their ears their ears are remarkably similar to our ears or rather our ears are remarkably similar to their ears the eyes of certain monkeys like macaque monkeys are remarkably similar to human eyes this is one of the reasons why if you look at a baby macaque monkey it look it has this unbelievably human element to it but the ears of these primates is very similar to our to our ears our ears similar to their ears if you're interested in ear movements and what they could mean and some of the things that ear movements correlate with in other aspects of our biology there's a nice paper actually scientific paper uh the the author's last name is code c-o-d-e it was published in 1995. i'll give a reference to that it's a review article that discusses some of the sex differences in ear movement control as well as the relationship between ear movements and eye movements and it's a pretty accessible paper it's one that i think any of you who are interested in this topic could um could parse fairly easily and there's some very interesting underlying biology and some theories as to why humans would have this so-called vestigial or ancient carryover of a system for moving our ears now if ear movement seems strange next i want to talk about a different feature of your hearing and ears that's even stranger but that has some really interesting implications for your biology and i'm guessing that you've not heard of this what i'm about to describe are called auto acoustic emissions and auto acoustic emissions as the name suggests are sounds that your ears make believe it or not 70 of people make noises with their ears but they don't actually detect them like i said you've never heard of this okay that's that's not what i mean but what i do mean is that 70 of people's ears are making noise that's cast out of the ear and these auto acoustic emissions actually can be detected by microphones sometimes they can be detected by other people in the room if they have very good hearing now it turns out that women or i should be technical here females who report as themselves as heterosexual have a higher frequency not frequency of sound but a higher frequency of auto-acoustic emissions than do men who report themselves as heterosexual women who report themselves as homosexual or bisexual make fewer auto acoustic emissions than heterosexual women these are data that come from dennis mcfadden's lab at the university of texas austin he actually discovered these what are called sexual dimorphisms and differences based on sexual orientation without looking for them he was studying hearing he's a auditory scientist and people were coming into his laboratory and they were detecting these autoacoustic emissions and they started to notice the group differences in auto-acoustic emission so they started asking people about their sex and about their sexual orientation and these differences fell out of the data as we say and it's interesting because auto acoustic emissions are not something that we associate with sex or sexual dimorphism but what these data really underscore is first of all a lot of us are making noises with our ears some of us more than others and that exposure to certain combinations of hormones during development are very likely shaping the way that our hearing apparati meaning the cochlea and the pinna and all sorts of things how those develop and how those function throughout the lifespan we did do an episode on hormones and sexual development which gets much deeper into the other effects that hormones have on the developing brain and body if you want to check out that episode we will put a link to it in the captions so now i want to shift to talking about ways to leverage your hearing system your auditory system so that you can learn anything not just auditory information but anything faster i get a lot of questions about so-called binaural beats binaural beats as their name suggests involve playing one frequency of sound to one ear and a different frequency of sound to the other ear so it might be to your right ear and it might be to the left ear and the idea is that the brain will take those two frequencies of sound and because the pathways that bring information from the ears into the brain eventually cross over they actually share that information with both sides of the brain that the brain will average that information and come up with a sort of intermediate frequency and the rationale is that those intermediate frequencies place the brain into a state that is better for learning and when i say better for learning i want to be precise about what i mean that could mean more focus for encoding or or bringing the information in we as you may have heard me say before we have to be alert and focused in order to learn there is no passive learning unless we're little tiny infants so can binaural beats make us more focused can binaural beats allow us to relax more if we're anxious i know some people they go to the dentist and the dentist offers binaural beats as they drill into your teeth and give root canals and things of that sort probably causing some anxiety just describing those those things right now but those are available in several dentists many dental practices their binaural beats have been thought to increase creativity or at least have been proposed to increase creativity so what are the scientific data say about binaural beats there are a number of different apps out there of that offer binaural beats there are a number of different programs you can i think you can also even just find these on on youtube and on the internet but typically it's an app and you'll program in a particular outcome that you want more focused more creative fall asleep less anxious etc so what do the scientific data say so believe it or not the science on binaural beats is actually quite extensive and very precise so sound waves are measured typically in hertz or kilohertz i know many of you aren't familiar with thinking about things in hertz or kilohertz but again just remember those waves on a pond those ripples on a pond if they're close together then they are of high frequency and if they're far apart then they are low frequency so when you hear more hurts what you're essentially hearing is higher frequency right and so if it's many more kilohertz then it's much higher frequency than if it's fewer hertz or killer hertz and so you may have heard of these things as delta waves or theta waves or alpha waves or beta waves etc delta waves would be big slow waves a low frequency and indeed there is quality evidence from peer-reviewed studies that are not sponsored by companies that make binaural beat apps that tell us that delta waves like one to four hertz so very low frequency sounds think costello's snoring can help in the the transition to sleep and for staying asleep and that theta rhythms which are more like 48 hertz can bring the brain into a state of subtle sleep or meditation so deeply relaxed but not fully asleep and then you can sort of ascend the staircase of findings here so to speak and you'll find evidence that alpha waves 8 to 13 hertz can increase alertness to a moderate level that's a great state for the brain to be in for recall of existing information okay and that beta waves 15 to 20 hertz are great for bringing the brain into focus states for sustained thought or for incorporating new information and especially gamma waves the highest frequency the most frequent ripples of sound so to speak 32 to 100 hertz for learning and problem solving now all of this matches or i should say maps onto what i've said before about learning really nicely which is that you need to be in a highly alert state in order to bring new information in in order to access a state of mind in which you can tell your brain or the brain is telling itself okay i need to learn this this is why stress and unfortunate circumstances are so memorable is because our brain gets into a really high alert system here we're talking about the use of binaural beats in order to increase our level of alertness or al or our level of calmness now that's important to underscore because it's not that there's something fundamentally important about the binaural beats they are yet another way of bringing the brain into states of deep relaxation through low frequency sound or highly alert states for focused learning with more high frequency sound so they are effective and i'll review a little bit of the data in detail they're effective but it's not that they're uniquely special for learning it's just that they can help some people bring their brain into the state that allows them to learn better so there are a lot of studies that allowed us to arrive or i should say allow the field to arrive on these parameters of you know slow slow low frequency waves are going to bring you into relaxed states high frequency waves into more alert states there's very good evidence for anxiety reduction from the use of binaural beats and what's interesting is the the anxiety reduction seems to be most effective when the binaural beats are bringing the brain into delta so those slow big waves like sleep theta and alpha states and i'll link to a couple of these studies although i will probably link um more to the list that really segregates them out one by one so you can see them all next to one another there's good evidence that binaural beats can be used to treat pain chronic pain there's three studies in peer-reviewed journals which i took a look at and they seem to be of good quality not sponsored research as we say not not paid for by any specific company binaural beats have been shown to modestly improve cognition attention working memory and even creativity but the real boost from binaural beats appears to be for anxiety reduction and pain reduction some people might find these beneficial for these oral surgeries right believe it or not there are people who would rather have the entire root canal or cavity drilled without novocaine and that's because they sometimes have a syringe phobia or something of that sort or they just don't like being numb from the novocaine or maybe there's an underlying medical reason but i think most people do don't enjoy getting their teeth drilled even if they have novocaine in there or a root canal and so it seems that binaural beats can be effective in that environment and you don't have to go into that sort of extreme environment to benefit from binaural beats binaural beats are a either relatively inexpensive thing to access most of the apps are pretty inexpensive i don't have a favorite binaural beats app to recommend to you i confess i did use binaural beats a few years ago i kind of shifted over to other what what i call nsdr non-sleep deep breast protocols in favor of those but many people like binaural beats and say that they benefit from them especially while studying or learning i think part of the reason for that relates to the ability to channel our focus when we have some background noise and this is something i also get asked about a lot is it better to listen to music and have background noise when studying or is it better to have complete silence well there's actually a quite good literature on this as well but not so much as it relates to binaural beats but rather whether or not people are listening to music so-called white noise brown noise believe it or not there's white noise and there's brown noise there's even pink noise and how that impacts brain states that allow us to learn information better or not so now i'd like to talk about white noise and i want to be very clear that white noise has been shown to really enhance brain states for learning in certain individuals in particular in adults but white noise actually can have a detrimental effect on auditory learning and maybe even the development of the auditory system in very young children in particular in infants so first i'd like to talk about the beneficial effects of white noise on learning there are some really excellent studies on this the first one that i'd like to just highlight is one that's entitled low intensity white noise improves performance in auditory working memory tasks an fmri study this is a study that explored whether or not learning could be enhanced by playing white noise in the background but the strength of the study is that they looked at some of the underlying neural circuitry and the activation of the neural circuitry in these people as they did the learning task and what it essentially illustrates is that white noise provided that white noise is of low enough intensity meaning not super loud right not imperceptible so not so quiet that you can't hear it but not super loud either it actually could enhance learning to a significant degree and this has been shown now for a huge number of different types of learning there's a terrific article as well as in a somewhat obscure journal at least obscure to me which is the effects of noise exposure on cognitive performance and brain activity patterns that's a study involving 54 subjects they basically were evaluated for mental workload and attention under different levels of noise exposure background noise and different essentially loudness of noise and the reason i like this study is that they looked at different levels of noise and types of noise and they varied a number of different things as opposed to just doing a kind of two condition either white noise or no white noise type thing and what they found again is that provided the white noise is not extremely loud it could really enhance brain function for sake of learning any number of different kinds of information now that's all great but it really doesn't get to the kind of deeper guts of mechanism and as a neuroscientist what i really want to see is not just that something has an effect that's always nice it's always nice to see in a nice peer-reviewed study without any kind of commercial biases that there's an effect okay binaural beats can enhance learning or listening to white noise not too loud can enhance learning but you really want to understand mechanism because once you understand mechanism not only does it start to make sense but you can also imagine ways in which you could develop better tools and protocols so i was very relieved to find or i should say excited to find this study published in the journal of cognitive neuroscience this is a 2014 paper white noise improves learning by modulating activity in dopaminergic midbrain regions and the right superior temporal sulcus okay i don't expect you to know what the right spirit temporal sulcus is i don't expect you to know what the dopamine midbrain region is but if you're like me you probably took highlighted notice of the word dopaminergic dopamine is a neuromodulator meaning it's a chemical that's released in our brain and body but mostly in our brain that modulates meaning controls the likelihood that certain brain areas will be active and other brain areas won't be active and dopamine is associated with motivation dopamine is associated with craving motivation is associated with all sorts of different things including movement but what this study so nicely shows is that white noise can really enhance the activity of neurons in what's called the substantia vta the substantia of eta is a very rich source of dopamine and that's because it's very chock-a-block full of dopamine neurons it's an area of the brain that is perhaps the richest source of dopamine neurons and you actually can see this brain region under the microscope if you take a slice of brain or you look at a brain without even staining it for any proteins or dopamine or anything it's a two very dark regions at the kind of bottom of the brain and the reason it's called substantia meaning dark is because the dopamine neurons actually make something and that makes those neurons dark and so you've got these two regions down there can that contain dopamine and can release dopamine and essentially activate other brain regions and activate our sense of motivation and activate our sense of desire to continue focusing and learning but you can't just snap your fingers and make them release dopamine you actually have to trigger dopamine release from them now that trigger can be caused by being very excited about something or the fact that that thing gave you a lot of pleasure in the past or you're highly motivated by fear or desire but what's so interesting to me is that it appears that white noise itself can raise the what we call the basal the baseline levels of dopamine that are being released from this area the substantia so now we're starting to get a more full picture of how particular sounds in our environment can increase learning and that's in part i believe through the release of dopamine from substantia so i'm not trying to shift you away from binaural beats if that's your thing but it does appear that turning on white noise at a low level not too loud you may say well how loud and i'll tell you in a moment but not too loud can allow you to learn better because of the ways that it's modulating your brain chemistry so how loud or how soft should that white noise be while you learn well in these studies it seemed that white noise that could be heard by the person so it wasn't imperceptible to them so it was loud enough that they could hear but not so loud that they felt it was intrusive or irritating to them okay so that's going to differ from person to person because people have different levels of auditory sensitivity it's going to depend on age gonna depend on a number of different factors so i can't tell you you know turn to level two on your volume controller that's just not gonna work also i don't know how far you are from a given speaker in the room or if you got earphones in your head or you've got speakers in the room or if it's coming out of your computer i don't know those things so what you're gonna have to do is adjust that white noise to a place where it's not interfering with your ability to focus but rather it's enhancing your ability to focus i think a good rule of thumb is going to be to put it probably in the lower third of any kind of volume dial as opposed to in the upper you know upper third where it would really be blasting and really blasting any noise frankly is not good but that's especially not good meaning it's especially bad if you have headphones in i do want to mention something about headphones before i talk about white noise in the developmental context and why it can be dangerous there when you put headphones in your ears it has this incredible effect of making the sounds like they come from inside your head not from out in the room and now that might seem like kind of a duh but that's actually really amazing right your brain assumes that the sounds are coming from inside your head as opposed from the environment that you're in the moment you put headphones in so if you're listening to an audio book or maybe you're listening to this podcast with headphones that's very different than when you're listening to something out in the room and there are other sounds other sound waves especially if you use these noise cancellation headphones so if you're going to use white noise to enhance studying or learning of any kind and this also could be for skill learning motor skill learning while you're exercising my suggestion would be that if you're using headphones to keep it quite low right this is an effect on the midbrain dopamine neurons that's a background effect of raising the baseline of dopamine release the way that dopamine neurons fires they're always firing yours are firing right now so are mine when something exciting happens they fire a lot and when something disappointing happens that firing the release of dopamine goes down below baseline what you're talking about here is raising your overall levels of attention and motivation which translate to better learning by just tickling those neurons a little bit raising the bass line firing okay so this isn't you're not turning up the white noise to the point where you're feeling amazing this isn't like turning on your favorite song this is actually the opposite this is about getting that bass line up just a bit okay so i recommend turning it the volume up just a bit so that you can focus entirely on the tasks that you're trying to do and of course you've turned on white noise so your attention might drift to that for a moment is it too loud is it too soft if you can disappear into the work so to speak if your attention can disappear into the work then that's probably sufficiently quiet and for those of you that say well i like really loud music and if i just blast the music then i forget about the music i don't suggest blasting music and this is coming from somebody who really likes loud you know loud music you know i grew up with kind of a loud fast rules mentality and if you don't know what loud fast rules means um then i can't help you but you it there's a time and a place perhaps to listen to music loud but especially with headphones you can trigger head you can trigger excuse me hearing loss quite rapidly and unfortunately because these hair cells that we talked about earlier are central nervous system neurons they do not regenerate they do not come back now along the lines of hearing loss i should just say that the best way to blow out your hearing for good to eliminate your hearing is to have very loud sounds superimposed on a loud environment okay so loud environments can cause hearing loss over time so if you work at a construction site clanging really loud or if you're if you uh work the sound board and in a club or something you are headed towards hearing loss unless you protect your your hearing with with ear plugs and headphones um nowadays some of the the earplugs are very low profile meaning you can't see them so that's kind of nice so you're not like the like when i was younger like you didn't want to be the dork to go to the concert with the earplugs but turns out those dorks were smarter than everybody else because they're not the ones who are you know craning their neck to try and hear trivial things um at the age of you know uh 30 or so because they blew out their hearing so if you are in working in a loud environment or you expose yourselves to a loud environment you really want to avoid big inflections and sound above that so loud environment plus fireworks loud environment plus gunshot loud and loud environments plus very high frequency intense sound that that's what we call the two-hit model when you this is also true for concussion that you can take a kind of a stimulus that normally would be below the threshold of injury you add some another stimulus at the same time that would be below the threshold of injury and then suddenly you killed the neurons so i i don't want to make people paranoid but you do want to protect your hearing it's no fun to lose your hearing if you're going to use headphones and you feel like you want to crank it up all the way just remember that the more that you can get out of a lower volume meaning the longer that you can go listening to things at lower volume the longer you'll be able to hear that music or that thing so again i'm not i'm not the hearing cop that's not my job but uh as somebody who's lost some of his uh high frequency hearing i can tell you it's it's it's not a pleasure um it the the old argument that it helps you not have to hear or listen to people that you don't want to listen to that does it doesn't really work they just send you text messages instead so what about white noise and hearing loss and development i know a lot of people with children have these kind of noise machines like sound waves and things like that that help the kids sleep and look i i think kids getting good sleep and parents getting good sleep is vital to physical and mental health and family health so i i certainly sympathize with with those needs however there are data that indicate that white noise during development can be detrimental to the auditory system i don't want to frighten any parents if you played white noise to your kids this doesn't mean that their auditory system or their speech patterns are going to be disrupted or that their interpretation of speech is going to be disrupted forever but there are data published in the journal science in science being one of the three apex journals science nature cell the most stringent journals data published in the journal science some years ago actually by a scientist who i know quite well his name is edward chang he's a medical doctor now he's a neurosurgeon he's actually the chair of neurosurgery at ucsf and he runs a laboratory where they study auditory learning neuroplasticity et cetera he and his mentor at the time mike merzinek published a paper showing that if young animals and this wasn't animal models were exposed to white noise so shh the very type of noise that i'm saying as a older person so and when i say older i mean somebody who's in their late teens early 20s and older could benefit from listening to that at a low level in the background for sake of learning well when they exposed very young animals to this white noise it actually disrupted the maps of the auditory world within the brain now we haven't talked about these maps yet but i want to take a moment and talk about them and explain this effect and what it might mean for you if you have kids or if you were exposed to a lot of white noise early on so auditory information goes up into our cortex into these the essentially the outside portion of our brain that's responsible for all our all of our how higher level cognition our planning our decision making etc creativity and up there we have what are called tonotopic maps what's a tonatopic map well remember the cochlea how it's coiled and at one end it responds to high frequencies in the other end it responds to low frequencies sort of like a piano the keys sound different as you extend down and up the piano keys and it's organized in a very systematic way right it's not all intermixed high frequencies and low frequencies it's it's organized in a very systematic way from one end to the other your visual system is in what's called a retinotopic map so neighboring points in space off to my right like my two fingers off to my right are mapped to neighboring points in space in my brain and the space right in front of me is mapped to a different location in my brain but it's systematic it's regular it's not random it's not salt and pepper it goes from high to lower from right to center to left in the auditory system we have what are called tonatopic maps where frequency high frequency to low frequency and everything in between is organized in a very systematic way now our experience of life from the time we're a baby until the time that we die is not systematic we don't hear low frequencies at one part of the room or at one part of the day and high frequency is another part of the room another part of the day they're all intermixed but if you remember the cochlea separates them out just like a prism of light separates out the different wavelengths of light the cochlea separates out the different frequencies and the developing brain takes those separated out frequencies and learns this relationship between itself meaning the child and the outside world white noise essentially contains no tonatopic information the frequencies are all intermixed it's just noise whereas when i speak my voice has now i'm getting technical but it has what's called a certain envelope meaning it has some low frequencies and some slightly high frequencies like i make my voice higher although i'm not very good at that my way starts to crack and i can make my voice lower although not as low as costello snores so it has an envelope it has a container white noise has no container it's like all the colors of the rainbow spread out together which is actually what you get when you get white light white noise is analogous to white light so one of the reasons why hearing a lot of white noise during development for long periods of time can be detrimental to the development of the auditory system is that these tonotopic maps don't form normally at least they don't in experimental animals now the reason i'm raising this is that many people i know in particular friends who have small children they say i want to use a white noise machine while i sleep but is is it okay for my baby to use a white noise machine and i consulted with various people scientists about this and they said well you know the baby is also hearing the parents voices and is hearing music and is hearing the dog bark so it's not the only thing they're hearing however every single person that i consulted with said but you know there's neuroplasticity during sleep that's when the kid is sleeping and i don't know that you'd want to expose a child to white noise the entire night because it might degrade that tonotopic map it might not destroy it it might not eliminate it but it could make it a little less clear like sort of taking the keys on the piano and taping a few of them together right so you still got the highs and lows in the appropriate order and everything in between but when you tape the keys together you don't get the same fidelity you don't get the same precision of the noise that comes out of that piano so i'm i don't again i don't want to scare anybody but i would say if you are in a position to make the choice of either using white noise or something similar pink noise is just a kind of variation it's got a little bit more of a certain frequency just like pink light has a little bit more of a certain wavelength than white light kind of if you are in a position to make choices about things to put in a young especially very young child sleeping environment white noise might be something to consider avoiding again i'm not telling you what to do but it's something to perhaps consider avoiding i don't think most pediatricians are going to be aware of these data but if you talk to any auditory physiologist or an audiologist or somebody who studies auditory development i'm fairly certain that they would have opinions about that now whether or not their opinions agree with mine and these folks that i consulted with or not is a separate matter i don't know because i don't know them but it's something that i felt was important enough to cue you to especially since i've highlighted i've highlighted excuse me the opposite effect is true in adulthood once your auditory system has formed once it's established these tonatopic maps then the presence of background white noise should not be a problem at all in fact it shouldn't be a problem at all because you're also not attending to it the idea is that it's playing at a low enough volume that you kind of forget it in the background and that it's supporting learning by bringing your brain into a heightened state of alertness and especially this heightened state of dopamine dopaminergic activation of the brain which will make it easier to learn faster and easier to learn the information so now i want to talk about auditory learning and actually how you can get better at learning information that you hear not just information that you see on a page or motor skill learning there are a lot of reasons to want to do this a lot of classroom teaching whether or not it's by zoom or in person is auditory in nature not everything is necessarily written down for us it's also good to get better at listening or so i'm told so there's a phenomenon called the cocktail party effect now even if you've never been to a cocktail party you've experienced and participated in what's called the cocktail party effect the cocktail party effect is where you are in an environment that's rich with sound many sound waves coming from many different sources many different things so in a city in a classroom in a car that contains people having various conversations you somehow need to be able to attend to specific components of those sound waves meaning you need to hear certain people and not others the reason it's called the cocktail party effect is that you and meaning your brain are exquisitely good at creating a cone of auditory attention a narrow band of attention with which you can extract the information you care about and wipe away or erase all the rest now this takes work it takes attention one of the reasons why you might come home from a loud gathering maybe a stadium a sports event or a cocktail party for that matter and feel just exhausted is because if you were listening to conversations there or trying to listen to those conversations while watching the game and people moving past you and hearing all this noise clinking of glasses etc it takes attentional effort and the brain uses up a lot of energy just at rest but it uses up even more energy when you are paying strong attention to something literally caloric energy burning up things like glucose etc even if you're ketogenic it's burning up energy so the cocktail party effect has been studied extensively in the field of neuroscience and we now know at a mechanistic level how one accomplishes this feat of attending to certain sounds despite the fact that we are being bombarded with all sorts of other sounds so there are a couple ways that we do this first of all much as with our visual system we can expand or contract our visual field of view so we can go from panoramic vision see the entire scene that we're we are in by dilating our gaze talked a lot about this on this podcast and elsewhere we can for instance keep our head and eyes stationary or mostly stationary you don't have to be rigid about it you can expand your field of view so you can see the walls and ceiling and floor you can see yourself in the environment that's panoramic view it's what you would accomplish without having to try at all if you went to a horizon for instance or we can contract our field of view i can bring my focus to a particular location when we call a virgin's point directly in front of me now i'm pointing at the camera directly in front of me okay we can do that we can expand and contract our visual field of view well we can expand and contract our auditory field of view so to speak or our auditory window you can try this next time you are in an environment that's rich with noise meaning lots of different sounds you can just tune out all the noise to a background chatter you kind of just you try not focus on any one particular sound and you get the background kind of chatter of noise and you'll find it's actually very relaxing in comparison to trying to listen to somebody at a cocktail party you're shouting back and forth now if you're very very interested in that person or getting to know them better or what they're telling you or some combination of those things then you'll be very motivated to do it but nonetheless it requires energy and effort and attention how do we do this well it's actually quite simple or at least it's simple in essence although the underlying mechanisms are complex here i have to credit the laboratory of a guy named mike weir w-e-h-r up at the university of oregon who essentially figured out that we are able to accomplish this extraction of particular sounds we can we can really hear one person or a small number of people amidst a huge background of chatter because we pay attention to the onset of words but also to the offset of words now the way to visualize this is if the background noise is just like a bunch of waves of noise it's literally just sound waves coming every frequency low frequency high frequency glasses clinking together if you had a game people are shouting people are talking on their phone there's the crack of the ball if somebody you know actually manages to to hit the ball oh the announcer etc but whatever we're paying attention to we set up a cone of auditory attention a kind of a tunnel of auditory attention where we are listening although we don't realize it we are listening for the onset and the offset of those words now this is powerful for a couple of reasons first of all it's a call to arm so to speak to disengage your auditory system when you don't need to focus your attention on something particular so if you are somebody you're coming home from work you've had a very long day and you're trying to make out a particular conversation on background noise you might consider just not having that conversation just letting your auditory landscape be very broad almost like panoramic vision if you're trying to learn how to extract sound information it could be notes of music it could be scales of music it could be words spoken by somebody else maybe somebody is telling you what you need to say for a particular speech or the information that you need to learn for a particular topic and they're telling it to you deliberately paying attention both to the onset and to the offset of those words can be beneficial because it it is exactly the way that the auditory system likes to bring in information so one of the more common phenomena that i think we all experience is you go to a party and or you meet somebody new and you say hi i would say hi i'm andrew and they'd say hi i'm i'm jeff for instance great great to meet you and then a minute later i can't remember the guy's name now is it because i don't care what his name is no somehow the presence of other auditory information interfered it's not that my mind was necessarily someplace else it's that the signal to noise as we say wasn't high enough somehow the way he said it or the way it landed on my ears which is really all that matters right when when it comes down to learning is such that it just didn't achieve high enough signal to noise the noise was too high or the signal was too low or some combination of those so the next time you ask somebody's name remember listen to the onset of what they say and the offsets it would be paying attention to the j in jeff and it would be paying attention to that in f in jeff excuse me all right and chances are you'll be able to remember that name now i don't know if people who are super learners of names do this naturally or not i don't have access to their brains i don't think they're going to give me access to their brains either but it's a very interesting way to take the natural biology of auditory attention and learning and apply it to scenarios where you're trying to remember either people's names or specific information now i do acknowledge that trying to learn every word in a sentence by paying attention to its onset and offset could actually be kind of disruptive to the learning process so this would be more for specific attention like you're asking directions in a city and somebody says okay you you know you say you're lost and they say okay you're gonna go two blocks down you're gonna turn left and then you're gonna see a landmark on your right and then you're gonna go um in the in the third door on your left that's a lot of information at least for me okay so the way you would you would want to listen to that is you're gonna go down the road you know i see i already forgot you're gonna take a le you're gonna go left and you're just going to program and instead of just hearing the word left you're going to think the l at the front of left and the t you're going to left okay and then so you're coding in specific words and what this does is this kind of hijacks these naturally occurring attention mechanisms that the auditory system likes to use it's a little bit of data that for auditory encoding this kind of thing can be beneficial there are a lot of data that attention for auditory coding is beneficial there are a little bit of data showing that deliberately encoding auditory information this way meaning trying to learn auditory information this way can be beneficial or can accelerate learning and some of these features of what i'm describing here map onto some of these work that of mike merzinick and others that have been designed to try and overcome things like stutter and to treat various forms of auditory learning disorders but more importantly and perhaps more powerful is the work of mike merzinick that was done with his then graduate student greg reckenzone that showed that using the attentional system we can actually learn much faster and we can actually activate neuroplasticity in the adult brain something that's very challenging to do and that the auditory system is one of the main ways in which we can access neuroplasticity more broadly so i just want to take a couple of minutes and describe the work of reckon zone and merzinik because it's absolutely fantastic and fascinating what they did is they had subjects try to learn auditory information except that they told them to pay attention to particular frequencies so now you know what frequencies are so essential essentially high-pitched sounds or low-pitched sounds what they found was just passively listening to a bunch of stuff does not allow the brain to change and for that stuff to be remembered at all that's not a surprise we've all experienced the you know the phenomena of having someone talk and we see their mouth moving like yeah this is really important that's really important we're listening we're trying to listen and then they walk away and we think i didn't get any of that and you wonder whether or not it was them maybe this is happening to you right now may you wonder whether or not it was you you wonder whether or not you have trouble with learning or you have attention deficit it could be any number of different things but what reckons own immersing discovered was that if you instruct subjects to listen for particular cues within speech or within sounds that not only can you learn those things more quickly but that you can remap these tonatopic maps in the cortex that i referred to earlier you actually get changes in the neural architecture the neural circuitry in the brain and this can occur not only very rapidly but they can occur in the adult brain which prior to their work was not thought to be amenable to change it was long thought that neuroplasticity could only occur in the developing brain but the work of reconcile and merzenik in the auditory system actually was some of the first that really opened up everybody's eyes and ears to the idea that the brain can change in adulthood so here's how this sort of process would work and how you might apply it if you are trying to learn music or you're trying to learn information that you're going to then recite you can decide to highlight certain words or certain frequencies of sound or certain scales or certain keys on the piano and to only focus on those for certain learning bouts okay so i'll give an example that's sort of real time for me meaning it's happening right now i know generally what i want to say when i arrive here i even know specifically certain things that i want to make sure get across to you but i don't think about every single word that i'm going to say and the precise order in which i'm going to say those things that would be actually very disruptive because it wouldn't match my normal patterns of speech and you'd probably think i was sounding rather robotic if i were to do that so one way that we can remember information is as we write out for instance something that we want to say we can highlight particular words we can underline those if we're listening to somebody and they are telling us information we can decide just to highlight particular words that they said to us and write those down now of course we're listening to all the information but the work of reckon zone and merzinek and the work of others in addition them is former student or former postdoc i don't know which uh michael kilgard who's now got his own lab down in texas or others have shown that the cueing of attention to particular features of speech particular components of speech the way in which it increases our level of attention overall allows us to capture more of the information overall and so i don't want this to be abstract at all what this means is when you're listening you don't have to listen to every word you're already listening to every word all the information is coming in through your ears what you're trying to extract is particular things or themes within the content so maybe you decide if you're listening to me that you're only going to listen to uh the word tools or you're only going to listen to when my voice kind of goes above background you get to decide what you decide to listen to or not and what you decide to focus on isn't necessarily as important as the fact that you're focusing so i hope that's clear the auditory system does this all the time with the cocktail party effect what i'm talking about is exporting certain elements of the mechanisms of the cocktail party effect paying attention to the onset and offset words or particular notes within music or particular scales or you can make it even broader and particular motifs of music or particular sentences of words or particular phrases and in doing that you extract more of the information overall even though you're not paying attention to all the information at once now i'd like to talk about a phenomenon that you've all experienced before which is called doppler so the doppler effect is the way that we experience sound when the thing that's making that sound is moving the simplest way to explain this is to translate the sound into the visual world once again so if you've ever seen a a duck or a goose sitting in a pond or a lake and it's kind of bobbing up and down what you'll notice is that the ripples of water that extend out from that duck or goose are fairly regularly spaced in all directions and that's because that ducker goose is stationary it's moving up and down but it's not moving forward or backward or to the side now if that duck or goose were to swim forward by paddling its little webbed feet under the surface you would immediately notice that the ripples of water that are close to and in front of that duck or goose would be closer together than the ones that trailed it that were behind and that is essentially what happens with sound as well with the doppler effect we experience sounds that are closer to us at higher frequency the ripples are closer together and sounds that are further away at lower frequency especially when they're moving past us so if you've ever for instance heard a siren in the distance that's essentially my rendition of a siren i don't know what ambulance or police or what passing you on a street that is the doppler effect the doppler effect is one of the main ways that we make out the direction that things are arriving from and their speeds and trajectories and we get very good from a very young age at discerning what direction things are arriving from and the direction that they are going to pass us in and the doppler effect has probably saved your life many many times in this way you just don't realize it because you'll step off the curb or you're driving your car and you pull to the side and so that the ambulance or fire truck can go by because you heard that siren off in the distance and then you pull away from the curb and you get back on the road in part because you don't see it any longer but also you don't hear any other sirens in the distance now some animals such as bats are exquisitely good and navigating their environments according to sound now we've all heard that bats don't see that's actually not true they actually have vision but they just rely more heavily on their auditory system and the way that bats navigate in the dark and the way that bats navigate using sound is through doppler now they don't simply listen to whether or not things are coming at them or moving away from them and pay attention to doppler like the siren example i gave for you what they do is they generate their own sounds so a bat as it flies around is sending out clicks i think that's my best bat sound or maybe is and they're clicking they're actually propelling sound out at a particular frequency that they know now whether or not they're conscious of it i don't know i've never asked them and if i did ask them i don't think they could answer and if they could answer they couldn't answer in a language that i could understand but the bat is essentially flying around sending out sound waves pinging its environment with sound waves of a particular frequency and then depending on the frequency of sound waves that come back they know if they're getting closer to an object or further away from it so if they send out sounds at a frequency of this was much slower than it would actually occur but you know let's say one every half second and it's coming back even faster then they know they're getting closer right because of the doppler effect and if it comes back more slowly they know that there's nothing in front of them so the bat is essentially navigating its world by creating these auras of sound that bounce back onto them from the various objects trees etc buildings and people it's kind of eerie to think about but yes they they see you with the experience you with their sound they sense you and they're using doppler to accomplish it now i'd like to talk about ringing in the ears this is something that i get asked about a lot and uh speaking of signal to noise i don't know if i get asked about it a lot because many people suffer from ringing in their ears or because the people who suffer from ringing in their ears suffer so much that they are more prone to ask so it could be a sampling bias i don't know but i've been asked enough times and some of the experiences of discomfort that people have expressed about having this ringing of the ears really motivated me to go deep into this literature so the ringing of the ears that one experiences is called tinnitus not tinnitus but tinnitus and tinnitus can vary in intensity and it can vary according to stress levels it can vary across the lifespan or even time of day so it's very subject to kind of background effects and contextual effects so i think you know we all know that we should do our best to maximize healthy sleep we did a number of episodes on that essentially the first four episodes of the huberman lab podcast we're all about sleep and how to get better sleep we all know that we should try and limit our stress and we had an episode about stress and ways to mitigate stress as well however there are people it seems that are suffering from tinnitus for which stress or lack of sleep just can't explain the presence of the tinnitus tinnitus can be caused by disruption to these hair cells that we talked about earlier or damage to the hair cells so that's another reason why even if you have good hearing now that you want to protect that hearing and really avoid putting yourself into these kind of two-hit environments environments where there's a lot of background noise and then you add another really loud auditory stimulus this also can happen at different times i should mention if you go to a concert where you listen to loud music with your headphones and then you go to a concert or you go into a very loud work environment the hair cells can still be vulnerable and once those hair cells are knocked out currently we don't have the technology to put them back although many groups including some excellent groups at stanford and elsewhere too of course are working on ways to replenish those hair cells and restore hearing there are treatments for tinnitus that involve taking certain substances there are medications for tinnitus in the non-prescription landscape which is typically what we discuss on this podcast when we discuss taking anything there are essentially four compounds for which there are quality peer-reviewed data where there does not appear to be any overt commercial bias meaning that nothing's reported in the papers as you know funding from a particular company and those are melatonin ginkgo bilboa zinc and magnesium now i've talked about melatonin before i'm personally not a fan of melatonin as a sleep aid but there are four studies first one entitled the effects of melatonin melatonin on tinnitus tinnitus excuse me and sleep second one treatment of central and sensory neural tinnitus with orally administered melatonin and then the title goes on much longer but it's a randomized study i'm not going to read out all these melatonin can it stop the ringing which is an interesting article double-blinded study and the effects of melatonin on tinnitus each one of these studies has anywhere from 30 to more than 100 subjects one case 102 subjects both genders as they list them out typically uh it's listed as sex not gender and studies so it should say both sexes but nonetheless um an age range anywhere from 30 years old all the way up to 65 plus i didn't see any studies of people younger than 30. all three focused on melatonin not surprisingly because of the titles looking at a range of dosages anywhere from three milligrams per day which is sort of typical of many supplements for melatonin still much higher than one would manufacture endogenously through your own pineal gland but three milligrams in these studies for a duration of anywhere from 30 days to much longer in some cases six months and all four of these studies found modest yet still statistically significant effects of taking melatonin by mouth so it's orally administered melatonin in reducing the severity of tinnitus so that's compelling at least to me i you know it doesn't sound like a cure and of course as always i'm not a physician i'm a scientist so i don't prescribe anything i only profess things i report to you the science you have to decide if melatonin is right for you if you have tinnitus and certainly i say that both to protect myself but also protect you you're responsible for your health and well-being and i'm not telling anyone to run out and start taking melatonin for tinnitus but it does seem that it can have some effects in reducing its symptoms ginkgo boa is an interesting compound it's you know it's been prescribed for or recommended for many many things but there are a few studies again double-blinded studies lasting one to six months any one that has an impressive number of subjects 978 subjects ranging from age 18 all the way up to 65. so on and so forth that show not huge effects of ginkgo but as they quote limited evidence suggests that if tinnitus is a side effect of something else in particular cognitive decline so age-related tinnitus might be helped by gingko bilboa i won't go through all the details of the zinc studies but it seems that zinc supplementation at higher levels than are typical of most people's intakes of 50 milligrams per day do appear to be able to reduce subjective symptoms of tinnitus in most of the people that took the supplemented zinc there aren't a lot of studies on that so i could only find one double-blinded study it lasted anywhere from one to six months 41 subjects both genders listed out again here 45 to 64. and they saw a decrease in the severity of tinnitus symptoms with 50 milligrams of elemental zinc supplementation and then last but not least is the magnesium study again only a single study it's a phase two study looking at a fairly limited number of subjects so only 19 subjects taking 532 milligrams of elemental magnesium for those of you that take magnesium there's magnesium and elemental magnesium and it's always translated on the on the bottle but it was associated with the lessening of symptoms related to tinnitus so for you tinnitus sufferers out there you may already be aware of this you may already be taking these things uh and had no positive effects meaning they didn't help maybe not i hope that um you'll at least consider these talk to your doctor about them i do realize that tinnitus is extremely disruptive i can't say i empathize uh because i don't from a place of experience that is because i don't have tinnitus but for those of you that don't including myself you can imagine that hearing sounds of things that aren't there and the ringing in one's ears can be very disruptive and i think um would be very disruptive and explains why people with tinnitus reach out so often with questions about how to alleviate that and i hope this information was useful to you i'd like to now talk about balance and our sense of balance which is controlled by believe it or not our ears and things in our ears as well as by our brain and elements of our spinal cord but before i do that i want to ask you another question or i would rather i'd like to ask you to ask yourself a question and answer it which is how big are your ears it turns out that the ears grow our entire life in the early stage of our life they grow more slowly and then as we age they grow more quickly you may have noticed if you have family members who are well into their 70s and 80s and if you're fortunate and you're into their 90s and maybe even hundreds is that the ears of some of these individuals get very very big relative to their previous ear sizes it turns out that biological age can actually be measured according to ear size now you have to take a few measurements but there's a believe it or not there is a formula in the scientific literature if you know your ear circumference so the distance around your ear ears plural presumably you have two most people do in millimeters so you're going to take the circumference of your ears and millimeters how would you do this right how would you do this maybe you take a string and you put it around your ear and then you measure the string that's probably going to be easier than marching around your ear or somebody else's ear with a ruler and measuring in millimeters so what's your ear circumference on the outside don't go in on the divot or anything you're just going around as if you're going to trace the the closest fitting oval assuming your ears are oval closest fitting oval that matches your ear circumference take that number in millimeters subtract from it oh excuse me i should do this correctly do that for both ears add them together add those numbers together divide by two get the average for your two ears get your average ear circumference and cross your two ears then take that number in millimeters subtract 88.1 and then whatever value that is multiply it times 1.96 and that will tell you your biological age now why in the world would this be accurate but as we age there are changes in number of different biological pathways one of those pathways is the pathways related to collagen synthesis so not only are our ears growing but our noses are growing too my nose seems to be growing a lot but then again i did sports where i would get my nose broken something i don't recommend so i always point out you don't get a nose like mine doing yoga but nonetheless my nose is still growing and my ears are still growing and i suspect as i get older if i have the good fortune of living into my 80s and 90s my ears are going to continue to grow a comparison between chronological age and biological age is something that's of really deep interest these days and the work of david sinclair at harvard medical school and others so-called horvath clocks that people have developed have tapped into how the epigenome in the genome can give us some insight into our biological age and how that compares to our chronological age most of us know our chronological age because we know when we were born and we know where we are relative to that now but you can start to make a little chart if you like about your rates of ear growth your rates of ear growth actually correlate pretty well with your rates of biological progression through this thing that we call life so it's not something that we think about too often but just like our dna and our epigenome and some other markers of metabolic health and hormone health relate to our age so does our collagen synthesis and one of the places that shows up the most is in these two little goodies on the sides of our heads which are our ears so even though it's a little bit of a bizarre metric it makes perfect sense in the biological context so let's talk about balance and how to get better at balancing the reason why we're talking about balance and how to get better at balancing in the episode about hearing is that all the goodies that are going to allow you to do that are in your ears they're also in your brain but they're mostly in your ears so as you recall from the beginning of this episode you have two cochlear cochleas that are one on each side of your head and that's a little spiral snail shape thing that converts sound waves into electrical signals that the rest of your brain can understand right next to those you have what are called semicircular canals the semicircular canals can be best visualized as thinking about three hula hoops with marbles in them so imagine that you have a hula hoop and it's not filled with marbles all the way around it's just got some marbles down there at the base okay so if you were to move that hula hoop around the marbles will move around okay you've got three of those and each one of those hula hoops has these marbles that can move around one of those hula hoops is positioned vertically with respect to gravity so it's basically parallel to your nose it sits like this if you're watching on a video but basically it's upright another one of those hula hoops is basically at a 90 degree angle to your nose it's basically parallel to the floor if you're standing up right now if you're seated okay and the other one is kind of tilted about 45 degrees in between those now why is the system there well those marbles within each one of those hula hoops can move around but they'll only move around if your head moves in a particular way and there are three planes or three ways that your head can move your head can move up and down like i'm nodding right now so that's called pitch it's pitching forward or pitching back okay so it's a nod up and down or i can shake my head no side to side that's called yaw you pilots will be very familiar with this yaw not yawn yaw and then there's roll tilting the head from side to side the way that a cute puppy might look at you from side to side okay or that if somebody doesn't really understand or believe what you're saying they might tilt their head very common phenomena i mean nobody does that to me but they they do that to each other so pitchian roll are the movements of the head in each of the three major planes of motion as we say and each one of those causes those marbles to move in one or two of the various hula hoops okay so if i move my head up and down when i nod one of those hula hoops literally right now the marbles are moving back and forth they aren't actually marbles by the way these are little um little kind of like little stones basically little calcium like deposits and when they roll back and forth they deflect little hairs little hair cells that aren't like the hair cells that we use for measuring sound waves they're not too different but they're not but they are different from them not like the hairs on our heads but they're basically rolling past these little hair cells and causing them to deflect and when they deflect downward the neurons because hair cells are neurons send information up to the brain so if i move my head like this there's a physical movement of these little stones in this hula hoop as i'm referring to it but they deflect these hairs send those hairs which are neurons those hair cells send information off to the brain if i'm ahead from side to side different little stones move if i roll my head different stones move this is an exquisite system that exists in all animals that have a jaw so any fish that has a jaw has this system a puppy has this system any animal that has a jaw has this so-called balance system which we call the vestibular system one of the more important things to know about the vestibular the balance system is that it works together with the visual system let's say i hear something off to my left and i swing my head over to the left to see what it is there are two sources of information about where my head is relative to my body and i need to know that first of all when i quickly move my head to the side those little stones as i'm referring to them i realize they're not actually stoned but as i'm referring to them they quickly activate those hair cells in that one semicircular canal and send a signal off to my brain that my head just moved to the side like this not that it went like this and pitched back or not that it tilted but it just moved to the side but also visual information slid past me my my field of view i didn't have to think about it but just slid past my field of view and when those two signals combine my eyes then locked to a particular location now if this is at all complicated you can actually uncouple these things it's very easy to do you can do this right now in fact i'd like you to do this experiment if you're not already doing something else that requires your attention and certainly don't do this if you're driving okay you're going to sit down and you're going to move your head to the left very slowly you're going with your eyes open so you're going to move it very very slowly the whole thing should take about five six maybe even 10 seconds to complete okay i just did it now i'm going to do it very quickly i'd like you to do it very quickly as well now do it slowly again okay what you probably noticed is that it's very uncomfortable to do it slowly but you can do it very quickly without much discomfort at all you just move your head to the side the reason is when you move your head very slowly those little stones at the base of that hula hoop they don't get enough momentum to move so you're actually not generating this signal to the brain that your head is moving and what you'll notice is that your eyes have to go boom boom boom jumping over step by step whereas if you move your head really quickly the signal gets off to your brain and your eyes just go boom right to the location you want to look at so moving your body slowly is actually very disruptive to the to the vestibular system and it's very disruptive to your visual system now if you've ever had the misfortune of being on a boat and you're going through big oscillations on the boat for those of you sick folks that get sea sick this can actually make certain people seasick just to hear about it that was big oscillations going up and down and up and down those are very disruptive we'll talk about nausea in a minute and how to offset that kind of nausea i get pretty seasick but there are ways that you can you can deal with this but this is incredible because what it means it's a purely physical system of these little stones rolling around in there and directing where your eyes should go okay so you can do this also just by looking up so let's just say you're sitting in a chair you're going to look up towards the ceiling and your eyes will just go there you're doing this eyes open you look down guys now try doing it really really slowly some people even get motion sick doing this which i if you do then just stop okay so you can do this also to the side although it works best if you're moving your head from from side to side um or nodding up and down so what we're doing here is we're uncoupling these two mechanisms we're pulling them apart the visual part and the vestibular part just to illustrate to you that normally these mechanisms in your inner ear tell your eyes where to go but as well your eyes tell your balance system your vestibular system how to function so i'd like you to do a different experiment experiment i'm not going to do it right now but basically stand up if you get the opportunity you can do this safely wherever you are you're going to stand up and you're going to look forward about 10 12 feet you can pick a point on a wall or you can um you know anywhere that you like if you're out in public you know just do it anyway you know just tell them you're listening to hubermann lab podcast and then someone's telling you to do it anyway if you don't want to do it don't do it but basically do it stand on one leg and lift up the other leg you can bend your knee if you like and just look off into the distance about 10 12 feet if you can do that if you can stand on one leg now close your eyes chances are you're going to suddenly feel what scientists call postural sway you're going to start swaying around a lot it is very hard to balance with your eyes closed you might think well and if you think about that it's like why is that that's crazy why would it be that it's hard to balance with your eyes closed well information about the visual world also feeds back onto this vestibular system so the vestibular system informs your vision and tells you where to move your eyes and your eyes and their positioning tell your balance system your vestibular system how it should function so there's a really cool way that you can learn to optimize balance you're not going to try and do this by learning to balance with your eyes closed what you can do is you can raise one leg and you can look at a short distance maybe off to just the distance that your thumb would be if you were to reach your arm out in front of you although you don't necessarily have to put your thumb in front of you so maybe just about two feet in front of you then while still balancing you're going to step your vision out a further distance and then a further distance and as far as you can possibly see in the environment that you're in and then you're going to march it back to you now what the literature shows is that this kind of balance training where you incorporate the visual system and extending out and then marching back in the point at which you direct your visual focus sends robust information about the relationship between your visual world and your balance system and of course the balance system includes not just these these hula hoops the semicircular canals but they communicate with the cerebellum this so-called mini brain actually means mini brain the back of your brain combines that with visual information and your map of the body surface that pattern of training is very beneficial for enhancing your ability to balance because the ability to balance is in part the activation of particular postural muscles but just as much perhaps even more so it's about being able to adjust those postural muscles muscles excuse me it's about the ability to adjust those postural muscles as you experience changes in your visual world and one of the most robust ways that you can engage changes in your visual world is through your own movement and so most people are not trying to balance in place right they're not just trying to stand there like a statue on one leg most of what we think about when we think about balance is for sake of sport or dynamic balance of being able to break ourselves and um when we're lunging in one particular direction to stop ourselves that is and then to move in another direction or for skateboarding or surfing or cycling or any number of different things gymnastics so the visual system is the primary input by which you develop balance but you can't do it just with the visual system so what i'm recommending is if you're interested in cultivating a sense of balance understand the relationship between these semicircular canals understand that they are both driving eye movements and they are driven by eye movements it's a reciprocal relationship and then even just two or three minutes a day or every once in a while even three times a week maybe five minutes maybe 10 minutes you pick but if you want to enhance balance you have to combine changes in your visual environment with a static posture standing on one leg and shifting your visual environment or static visual view looking at one thing and changing your body posture okay so those two things we now know from the scientific literature combine in order to give an enhanced sense of balance and there's a really nice paper that was published in 2015 called effects of balance training on balance performance this was in healthy adults it's a systematic review and a meta-analysis a meta-analysis is when you combine a lot of literature from a lot of different papers and extract the really robust and the less robust statistical effects so it's a really nice paper as well there are some papers out there uh for instance uh comparison of static balance and the role of vision in the elite athletes this is um essentially the paper that i've extracted most of the information that i just gave you from and that paper and there are some others as well um but basically i distilled them down into their core components the core components are move your vision around while staying static still but in a balanced position like standing on one leg could be something more complicated if you're somebody who can do more complicated movements unilateral movements seem to be important so standing on one leg as opposed to both right or trying to generate some tilt is another way to go about it or imbalance meaning one limb asymmetrically being activated compared to the other limb and then the other way to encourage or to cultivate and build up this vestibular system and your sense of balance actually involves movement itself acceleration so that's what we're going to talk about now so up until now i've been talking about balance only in the static sense like standing on one leg for instance but that's a very artificial situation even though you can train balance that way most people who want to enhance their sense of balance for sport or dance or some other endeavor want to engage balance in a dynamic way meaning moving through lots of different planes of movement maybe even sometimes while squatting down low or jumping and landing or making trajectories that are different angles for that we need to consider that the vestibular system also cares about acceleration so it cares about head position it cares about eye position and where the eyes are and where you're looking but it also cares about what direction you're moving and how fast and one of the best things that you can do to enhance your sense of balance is to start to bring together your visual system the semicircular canals of the inner ear and what we call linear acceleration so if i move forward in space rigidly upright it's a vastly different situation than if i'm leaning to the to the side one of the best ways to cultivate a better sense of balance literally within the sense organs and the neurons and the biology of the brain is to get into modes where we are accelerating forward typically it's forward while also tilted with respect to gravity now this would be the carve on a skateboard or on a surfboard or a snowboard this would be the taking a corner on a bike while being able to lean safely of course lean into the turn so that your head is actually tilted with respect to the earth so anytime that we are rigidly upright we aren't really exercising the vestibular system imbalance this is why you know you see people in the gym on these um one of those bouncy balls bocce ball bouncy ball is the one that the guys roll in the park right bouncy balls where they're bouncing back and forth that will work the small stabilizing muscles but what i'm talking about is getting into modes where you actually tilt the body and the head with respect to earth what i mean is with respect to earth's gravitational pull now the cerebellum is a very interesting structure because not only is it involved in balance but it's also involved in skill learning and in generating timing of movements it's a fascinating structure deserving of an entire episode or several episodes all on its own but some of the outputs of the cerebellum meaning the neurons in the cell cerebellum get inputs but they also send information out the outputs of the cerebellum are strongly linked to areas of the brain that release neuromodulators that make us feel really good in particular serotonin and dopamine and this is an early emerging subfield within neuroscience but a lot of what are called the non-motor outputs of the cerebellum have a profound influence not just on our ability to learn how to balance better but also how we feel overall so for you exercisers out there i do hope people are getting regular healthy amounts of exercise we've talked about what that means in previous episodes so at least 150 minutes a week of endurance work some strength training a minimum of five sets per body part to maintain musculature even if you don't want to grow muscles you want to do that in order to maintain healthy strength and bones etc if you're doing that but you're only doing things like curls in the gym squats in the gym riding the peloton or even if you're outside running and you're getting forward acceleration but you're never actually getting tilted right you're never actually getting tilted with respect to earth's gravitational pull you're not really exercising and getting the most out of your nervous system activation of the of the cerebellum in this way of being tilted or the head being tilted in the body being tilted while in acceleration typically forward acceleration but sometimes side to side has a profound and positive effect on our sense of mood and well-being and as i talked about in a previous episode it can also enhance our ability to learn information in the period after generating those tilts and that acceleration and that's because the cerebellum has these outputs to these areas of the brain that release these neuromodulators like serotonin and dopamine and they make us feel really good i think this is one of the reasons why growing up i had some friends some of whom might have been you know the world heavyweight champions of laziness for essentially everything except they would wake up at 4 30 in the morning to go surf they would like drive they would get up so early to go surf i al it's not just surfers um and some surfers by the way i should point out are not lazy humans they do a lot of other things but i knew people that couldn't be motivated to do anything but they were highly driven to get into these experiences of forward acceleration while tilted with respect to gravity likewise with snowboarding or skiing or cycling those modes of exercise seem to have an outsized effect both on our well-being and our ability to translate the vestibular balance that we achieve in those endeavors to our ability to balance while doing other things so and i don't mean psychological balance necessarily i mean physical balance so for those of you that don't think of yourselves as very coordinated or with very good balance getting into these modes of acceleration forward movement or lateral movement while getting tilted even if you have to do it slowly it could be beneficial i do believe and the scientific literature points the fact that it will be beneficial for cultivating better sense of physical balance it can really build up the circuits of this vestibular system and then of course the feel-good components of acceleration while tilted or while getting the head into different orientations relative to gravity well that's the explanation for roller coasters some people hate roller coasters they make them feel nauseous many people love roller coasters and one of the reasons they love roller coasters is because of the way that when you get the body even if you're not generating the movement you get the body into forward acceleration and you're going upside down and tilted to the side as the tracks go from side to side and tilt etc you're getting activation of these deeper brain nuclei that trigger the release of neuromodulators that just make us feel really really good in fact some people get a long arc a long duration kind of buzz from having gone through those experiences some people who hate roller coasters are probably getting nauseous just hearing about that so i encourage people to get into modes of acceleration while tilted every once in a while provided you can do it safely it's an immensely powerful way to build up your skills in the realm of balance and it's also for most people very very pleasing it feels really good because of the chemical relationship between forward acceleration and head tilt and body tilt now speaking of feeling nauseous some people suffer from vertigo some people feel dizzy some people get lightheaded an important question to ask yourself always if you're feeling quote unquote dizzy or lightheaded is are you dizzy or are you lightheaded now we're not going to diagnose anything here because there's just no way we can do that this is essentially me shouting into a tunnel so we don't know what's going on with each and every one of you but if ever you feel that your world is spinning but that you can focus on your thumb for instance but the rest of the world is spinning and your thumb is stationary that's called being dizzy now if you feel like you're falling or that you feel like you need to get down onto the ground because you feel light-headed that's being lightheaded and often times with language we don't distinguish between being dizzy and being light-headed now there are a lot of ways that dizziness and lightheadedness can occur and i don't even want to begin to guess at the number of different things and ways that it could happen for those of you that suffer from it because it could be any number of them but oftentimes if people are light-headed yes it could be low blood sugar it could also be that you're dehydrated it could also be that you are low in electrolytes we talked about this in a previous episode but we will talk about it more in a future episode many people have too little sodium in their system salt and that's why they feel light-headed i have family members who for years thought they had disrupted blood sugar they would get shaky jittery lightheaded feel like they were nauseous etc and simply the addition of a little sea salt to their water remedied the problem entirely i don't think it's going to remedy every issue of lightheadedness out there by any stretch but just the addition of salt in this particular case help the person and they are not alone many people who think that they have low blood sugar actually are light-headed because of low electrolytes and because of the way that salt carries water into the system and creates changes in blood volume etc low sodium can often be a source of light-headedness as can low blood sugar and of course other things as well now for dizziness or seasickness we were all taught that you need to pick a point on the horizon and focus on it but actually that's not correct it is true that if you are down in the cabin of a boat or you're on the lower deck and all you can see are things up close to you that getting sloshed around like so or the boat going up and down like so i think i'm getting a little seasick even as i do this and i describe it focusing on things close to you can be problematic and in that case the advice to go up on deck and get fresh air and to look off into the horizon that part is correct but focusing your eyes on a particular location on the horizon is effectively like trying to move very slowly as i had you do before where you're trying to move your head very slowly while fixating on one location your eyes and your balance system were designed to move together so really what you want to do is allow your visual system to track with your vis your vestibular system this is why sitting in the back of an uber or a taxi and being on your phone can make you suddenly feel very nauseous sometimes the cabs particularly in new york city they have a lot of occluders they have a lot of stuff blocking your field of view there's usually a little portal out there where you can see out to the front of the of the uh of the front windshield but there's all this stuff now televisions in the back seat and you're watching that television and the cab is moving you're in linear acceleration and sometimes you're taking corners you're breaking so then your your vestibular system has to adjust to that if you're looking at your phone or a book or even if you're talking to somebody actually i'm starting to feel a little nauseous i'm gonna i promise i'm not gonna finish this episode by vomiting at the end at least not here but what you what can happen is that you're uncoupling your v the visual information from your motion from your vestibular information you want those to be coupled this is why a lot of people have to drive they can't be in the passenger seat because when you drive you also get what's called proprioceptive feedback your body is sending signals also to the vestibular system about where you are in space when you're the passenger you're just getting jolted around as the person is driving and if you're looking at your phone it's even worse and if you're looking at the occluder between you and the two front seats that's even worse so this is why staring out the front windshield is great but you don't want to fixate okay so hopefully i um spared a few people and hopefully a few cab drivers of having people get sick in their cars or ubers let your visual system and your vestibular system work together if appropriate get into linear acceleration and you'll improve your sense of balance once again we've covered a tremendous amount of information now you know how you hear how you make sense of the sounds in your environment how those come into your ears and how your brain processes them in addition we talked about things like low-level white noise and even binaural beats which can be used to enhance certain brain states certain rhythms within the brain and even dopamine release in ways that allow you to learn better and we talked about the balance system and this incredible relationship between your vestibular apparatus meaning the portions of your inner ear that are responsible for balance and your visual system and gravity and you can use those to enhance your learning as well as well as just to enhance your sense of balance if you're learning from this podcast please subscribe on youtube that really helps us in addition please leave us any comments or feedback or suggestions for future episode content on youtube in the comment section if you haven't already subscribed on apple and spotify please do that as well and on apple you have the opportunity to leave us up to a five star review at apple you can also leave us comments and feedback during this episode i mentioned some supplements we partnered with thorn because thorn has the very highest levels of stringency with respect to the quality of their ingredients and accuracy about the amounts of those ingredients contained within their products if you'd like to see the products that i take from thorn you can go to t-h-o-r-n-e dot com slash the letter u huberman so that's thorne dot com slash u slash huberman to see all the supplements that i take and if you do that you can get twenty percent off any of those supplements or 20 off any of the supplements that thorn makes for those of you that might want to support us in other ways we have a patreon account it's patreon.com andrewhuberman and there you can support our podcast at any level that you like in addition if you'd like to support the podcast please check out our sponsors mentioned at the beginning of the episode that is absolutely the best way to support us last but not least i'd like to thank you for your time and attention and desire and willingness to learn about vision and balance and of course thank you for your interest in science