Episode 27: The Science Of Hearing, Balance & Accelerated Learning | Huberman Lab

Key Takeaways

  • Difference of the timing and frequency at which sound arrives at ear allows you to make out the direction sound is coming from
  • White noise at low intensity (level you can hear but is not intrusive) can enhance learning in adults
  • Depending on the soundwave frequency – binaural beats can put the brain in a better state to increase cognition, relaxation, creativity, reduce pain and anxiety
  • Low frequency waves put the brain into a relaxed state versus high frequency soundwaves which put the brain into more alert states
  • You can train hearing by deliberately paying attention to onset and offset of words
  • Visual system and auditory system work together for balance
  • Best options to train balance: (1) stand stationary on one leg and look at various points in distance; (2) keep eyes fixed and change body position; (3) tilt the body and head at and angle – such as skateboarding, snowboarding, surfing
  • The size of your ear is an indication of biological age and aging

Introduction

Dr. Andrew Huberman, Ph.D. is a Professor of Neurobiology and Ophthalmology at Stanford University School of Medicine. His lab focuses on neural regeneration, neuroplasticity, and brain states such as stress, focus, fear, and optimal performance.

In this episode of Huberman Lab, Dr. Huberman breaks down the mechanism of hearing and making sense of sounds as well as things that can go wrong with hearing. He also discusses ways to accelerate learning using sound and the mechanics of our ears.

Host: Andrew Huberman (@hubermanlab)

Anatomy And Function Of Ear

  • The technical name of the ear is pinna
  • Ear size changes across lifespan and is an indication of how fast you are aging
  • Ears amplify high and low frequency sounds
  • Soundwaves (fluctuations in the way air is moving) are captured by ears, eardrum, and hammer
  • The cochlea (snail shaped structure) in ear is where soundwaves get converted to something brain can understand
  • Cochlea separates low frequency from high frequency
  • Soundwaves come in, eardrum moves on hammer, hammer bangs on cochlea and separate types of sound for processing by brain
  • There are many stations in which auditory information is processed before it becomes something we understand
  • Our brain is not only processing what the sound is, but also where it is coming from
  • Auditory and visual system collaborate to understand where things are taking place in space
  • Ventriloquism effect: you think a sound is coming from location that it’s not
  • Inter-oral time difference: stations in brain calculate time of arrival in left ear versus right to help understand what direction sound is coming from
  • The shape of your ear modifies sound depending on where it is coming from

Auto-Acoustic Emission And Sexual Orientation

  • Auto-acoustic emissions: sounds cast out by ears, not heard by the person making the sound
  • 70% of people make noises with their ears
  • Certain combinations of hormones during develop are likely shaping hearing and processing
  • Heterosexual women have a higher rate of auto-acoustic emissions
  • Homosexual or bisexual women have a lower rate of auto-acoustic emissions

Leverage Hearing For Faster Learning

  • Binaural beats: playing one sound in one ear and a different sound in the other ear
  • Binaural beats place the brain into a state that is better for learning
  • Some dentists offer binaural beats for improved relaxation
  • Binaural beats have been shown to increase cognition, relaxation, creativity, pain reduction, anxiety reduction
  • Good evidence supporting the use of binaural beats for anxiety reduction (particularly delta, theta, alpha)
  • Apps have been created which will create sounds based on desired outcome – e.g., relaxation, anti-anxiety, sleep, etc.
  • Binaural soundwaves from lowest to highest frequency:
    • Delta waves (low frequency sounds) can help transition to sleep and staying asleep
    • Theta waves can assist with non-sleep rest – good for meditation
    • Alpha waves can increase alertness – great for recall of existing information
    • Beta waves are great for bringing the brain into focus for complex learning
    • Gamma waves are good for learning and problem solving
    • You need to be in highly alert state to bring new information in – higher soundwaves stimulate advanced learning
  • Low frequency waves put the brain into a relaxed state versus high frequency soundwaves which put the brain into more alert states
  • Possibly because we can channel focus better with background noise

White Noise, Learning & Development

  • White noise has been shown to enhance brain wave states for learning in adults – but – possibly detrimental in young children and infants
  • White noise at low intensity can enhance learning
  • White noise may modulate activity in regions of the brain, including dopaminergic pathway (area of the brain involved in motivation, reward)
  • White noise can raise base levels of dopamine released
  • Sounds in environment can increase learning through dopamine
  • Tip: if using headphones, keep particularly low because the brain is perceiving the sound to come from your head which can be stimulating
  • There is data that white noise can be detrimental to mapping of auditory system of brain in children
  • Not worth the risk of using white noise machine to help infants and children sleep through the night

How To Improve Auditory Learning

  • Cocktail party effect: in an environment rich with sounds, you need to pay attention to certain sounds (and people) and not others
  • The brain is good at extracting information we need and ignoring the rest, but it takes a lot of energy
  • Much like we can expand visual field, we can expand and contract auditory field – actively tune out background noise or chatter
  • Train your hearing: disengage auditory system when you don’t need to focus on something particular
  • To improve auditory learning: deliberately pay attention to onset and offset of words – for example, the “J” and “f” sounds in Jeff when someone introduces themselves by name
  • Passively listening does not allow brain to process information and commit to memory
  • Listen for particular cues within speech and sound to change neurocircuitry in brain
  • Highlight certain words or frequency of sound to improve learning

Vestibular System (Balance)

  • Balance starts in the ears
  • Three planes head can move along: pitch (nod up and down), yan (shake side to side), roll (tilt side to side)
  • Depending on what direction the head is moving, different signal is sent to brain
  • Vestibular system works with visual system
  • Try moving your head fast then slow and notice the difference in difficulty and discomfort
  • Mechanisms in inner ear tell eyes where to go then eyes tell balance system how to function
  • It’s hard to balance with eyes closed because information about visual world feeds back into vestibular system
  • To optimize balance: raise one leg and look off short distance and gradually increase gaze – then bring gaze back in closer
  • Tip 1 to enhance balance: combine changes in visual environment while stationary (i.e., standing on one leg)
  • Tip 2 to enhance balance: look at one thing and change body posture

Dynamic Ways To Enhance Balance

  • Vestibular system cares about acceleration – what direction you are moving and how fast
  • One of the best ways to cultivate a better sense of balance is to get into modes we are accelerating forward and tilted – such as skateboard, snowboard, surfboard, lean into turn on bike
  • Tilt the body and the head with respect to earth’s gravitational pull
  • Learning and ability to learn is enhanced in periods after these modes of exercise

Doppler Effect

  • Doppler effect: the way we are experiencing sound when the thing making the sound is moving
  • Firetruck, police, and ambulance sirens are a good example of Doppler
  • We experience sounds closer to us at higher frequency and sounds that are further away at lower frequency
  • Doppler effect is one of the main ways we assess what direction, speed, and trajectory sound is coming from
  • Bats navigate world mostly by making sound and Doppler to communicate

Ringing In Ears (Tinnitus)

  • Tinnitus is subject to context and can vary throughout time of day, environment, sleep and even stress
  • Tinnitus can be caused by disruption to hair cells in the ears
  • Non-prescription treatments: melatonin, gingko biloba, zinc, magnesium
    • Melatonin – 3mg per day
    • Zinc – 50 mg per day
    • Magnesium – 532mg per day
  • Ginkgo biloba seems particularly beneficial in age-related tinnitus

Vertigo, Nausea, Dizziness And Other Ailments

  • Being dizzy and lightheaded have to be differentiated
  • Dizzy: if the world is spinning but you can focus on thumb
  • Lightheaded: if you feel like you’re falling or need to get on the ground
  • Some causes of lightheadedness: dehydrated, low in electrolytes, low blood sugar – try adding a little salt to water
  • To help with nausea, sea sickness, motion sickness: track eyes with the direction you are moving

Aging And Size Of Ears

  • The ears grow throughout your life
  • Biological age can be measured according to ear size – circumference of outer ears (both) in millimeters then take the average and subtract 88.1 x 1.96
    • Biological age = average of circumference of both ears in millimeters – 88.1 x 1.96

Hearing Loss

  • Loud sounds and loud environment will eventually lead to hearing loss
  • Avoid big inflections of sounds above what you have to endure – for example, controlling soundboard at a concert then adding in fireworks

Spacing Effect: Rest To Enhance Learning

  • To learn a new skill, you have to practice and get many repetitions
  • Taking rest within the learning block is also important – e.g., do nothing (not even look at phone) for 10 seconds between reps
  • Rest ties learning and improvement of skill to underlying improvement of neuron
  • Hippocampus and cortex are active during rest and processing repetition at 20x the speed
  • The brain is willing to give us the learning we want as long as we also let it rest
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Notes By Maryann

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