The Science of Hearing, Balance & Accelerated Learning | Huberman Lab Podcast #27

Summary

• The auditory system (hearing) and the vestibular system (balance) can be used to improve learning and memory
• A recent study published in Cell Reports suggests taking breaks within a learning episode can improve skill learning
• The vestibular system and auditory system are interconnected and can affect each other
• The vestibular system is involved in spatial awareness, balance, and eye movements
• The auditory system is involved in hearing and spatial awareness
• 70% of people produce otoacoustic emissions (noises made by the ear) that can affect others
• Tinnitus (ringing in the ears) can be a symptom of various underlying issues and can be treated with various methods
• Listening to certain types of music can help with learning and memory
• The vestibular system can be trained through exercises and movements
• The brain is willing to generate repetitions for learning, but needs rest periods to do so effectively
• It may be beneficial to take a 20-minute break or nap after a period of learning
• Introduction to hearing and balance
• Roka eyewear and InsideTracker are sponsors of the podcast
• The ear has three main parts: the outer, middle, and inner ear
• The ear is responsible for both hearing and balance
• The inner ear contains the vestibular system, which is responsible for balance
• The vestibular system contains three semi-circular canals and the otolith organs (utricle and saccule)
• The semi-circular canals detect rotational movement, while the otolith organs detect linear acceleration
• The vestibular system sends information to the brain about the body's movement and position in space
• The ear also contains the cochlea, which is responsible for converting sound waves into electrical signals that can be interpreted by the brain
• The cochlea contains hair cells that vibrate in response to sound waves, which then trigger the release of neurotransmitters that send the electrical signals to the brain
• Damage to the ear or vestibular system can lead to hearing and balance disorders
• The ear and vestibular system can adapt and compensate for damage or dysfunction, but this process can take time and may not be fully successful.
• The ear captures sound waves and converts them into electrical signals that the brain can understand
• Sound waves come in through the ear and move the eardrum, which is a membrane
• The eardrum is connected to a hammer-like structure called the malleus, incus, and stapes
• The hammer hits the cochlea, which is a snail-shaped structure in the inner ear
• The cochlea has hair cells that move and send signals to the brain when they detect a sound
• The cochlea is coiled and varies in rigidity along its length, which allows it to differentiate between high and low frequency sounds
• The cochlea's base is more rigid and responds to high frequency sounds, while the apex is more flexible and responds to low frequency sounds
• The auditory system processes auditory information in order to determine the location of sounds in space
• The visual system can also help determine the location of sounds
• The ventriloquism effect occurs when the perceived location of a sound does not match its actual location
• The brain uses interaural time differences to determine the direction of a sound
• The shape of the ear modifies sound waves and helps determine the elevation (up and down position) of a sound
• Cupping the hand around the ear can improve sound localization by creating a larger pinna (ear shape)
• Sound localization is important for survival because it allows us to determine the location of potential threats or resources
• Otoacoustic emissions are sounds made by the ear that can be detected by microphones and some people with good hearing
• Hormone exposure during development may shape the development and function of the ear and hearing apparati
• Binaural beats involve playing one frequency of sound to one ear and a different frequency to the other ear
• The brain combines the frequencies and creates a third, "beat" frequency, which is believed to have an effect on brain waves and potentially alter consciousness
• There is limited scientific evidence to support the effectiveness of binaural beats
• Other methods for leveraging the auditory system to facilitate learning include:
• Using music to improve memory and focus
• Using rhythm and rhyme to aid in the memorization of information
• Using spoken language to learn new information, particularly in conjunction with visual aids
• Binaural beats can be effective for bringing the brain into states of deep relaxation or alertness for focused learning
• Binaural beats can reduce anxiety and pain, and may modestly improve cognition, attention, working memory, and creativity
• White noise can enhance brain states for learning in adults but can have a detrimental effect on auditory learning and development in young children
• Music can be beneficial or detrimental to learning depending on the type of task and personal preference of the listener
• People may find background noise helpful for focusing while studying or learning, but complete silence may also be beneficial depending on the individual
• White noise can increase basal levels of dopamine released from the substantia nigra, potentially aiding in learning and focus.
• White noise should not be too loud or intrusive, but audible enough to be heard.
• Headphones can cause sounds to seem like they are coming from inside the head, which can be dangerous in the developmental context.
• White noise may be helpful for studying or learning new skills, but should be used at low volumes with headphones.
• Too much white noise can be damaging to the auditory system and cause hearing loss.
• White noise may be helpful for sleep, but it is not a replacement for addressing the root cause of sleep issues.
• White noise may be detrimental to the auditory system during development.
• There is scientific research published in the journal Science that shows that exposure to white noise can disrupt the maps of the auditory world in the brain in young animals.
• These maps, called tonotopic maps, are important for organizing auditory information in the brain in a systematic way.
• White noise does not contain tonotopic information, as it is made up of all frequencies mixed together, rather than being organized by frequency.
• It is not clear if the effects of white noise on auditory development observed in animals also apply to humans.
• The cocktail party effect refers to the ability to selectively attend to certain sounds in a noisy environment
• The brain uses a lot of energy to pay attention, especially in a noisy environment
• The brain can expand or contract its auditory field of view, similar to how the visual system can expand or contract its field of view
• The brain can selectively attend to certain sounds by focusing on the onset of words
• The brain can also use prosody, or the rhythm and melody of speech, to differentiate between different speakers
• The brain can also use prior knowledge and expectations to filter out irrelevant sounds
• The attentional system can be used to learn information more quickly and activate neuroplasticity in the adult brain, particularly in the auditory system
• Mike Merzenich and graduate student Gregg Recanzone conducted research showing that subjects instructed to listen for specific cues within speech or sounds were able to learn and remember information more quickly and make changes in neural circuitry in the brain
• Techniques for using the attentional system to enhance learning and memory include focusing on specific words or frequencies of sound, chunking information, and using mnemonic devices
• The use of music or rhythm can also aid in learning and memory, particularly when combined with other techniques such as focusing on specific sounds or using mnemonic devices
• Bats use their auditory system to navigate their environment, sending out and receiving sound waves to determine the location of objects in their surroundings
• Tinnitus is a condition characterized by ringing in the ears and can vary in intensity and be influenced by stress levels and time of day
• Tinnitus can be caused by damage to the hair cells in the ear or by other factors such as age-related hearing loss or exposure to loud noises
• Treatment options for tinnitus include managing stress, avoiding loud noises, and using sound therapy or masking devices
• Medications and supplements may also be used to treat tinnitus, but their effectiveness varies and they may have side effects
• Tinnitus retraining therapy is a treatment that aims to change the brain's perception of tinnitus and reduce its negative effects on a person's life
• Zinc supplementation (50 milligrams) may decrease severity of tinnitus symptoms in people
• Magnesium supplementation (532 milligrams) may lessen tinnitus symptoms
• Ear size can be used to measure biological age
• Changes in collagen synthesis, changes in ear canal size, and changes in the vestibular system can all contribute to changes in balance and sense of balance as we age
• Exercise, especially balance-related exercises, can help maintain balance and prevent falls in older people
• Tai chi and yoga may be particularly helpful in improving balance in older individuals