The Science of Hearing, Balance & Accelerated Learning

KEYPOINTS

• 01

  Short rests during practice speed up skill learning

  A Cell Reports study from a lab led by a neuroscientist named Cohen (Huberman jokes, not the musician Leonard Cohen) had people practise a piano-key sequence (G-D-F-E-G) either continuously or in 10-second bursts separated by 10 seconds of doing nothing. Learning and retention were much faster with the breaks. Brain imaging showed the hippocampus and cortex replaying the sequence about 20 times faster during rest, which the authors call 'micro-offline gains.' It builds on the spacing effect Ebbinghaus first described in 1885.

• 02

  The cochlea sorts sound by frequency like a prism

  The pinna's shape amplifies high frequencies. Sound vibrates the eardrum and the three small bones (malleus, incus, stapes), which press on the fluid-filled cochlea. One end of the cochlea responds to high pitches and the other to low, much like piano keys. The auditory cortex keeps that order in 'tonotopic maps.' Hair cells lost to damage can't currently be replaced, though groups including some at Stanford are working on it.

• 03

  Binaural beats change brain state, but they aren't learning magic

  Huberman says the independent, non-sponsored research is surprisingly solid. Delta frequencies (1–4 Hz) help with falling and staying asleep, theta (4–8 Hz) brings on a meditative state, and higher frequencies, up to gamma (32–100 Hz), support alertness, focus and problem-solving. The strongest benefits are for reducing anxiety, including at the dentist, and reducing chronic pain (three good-quality studies). Effects on cognition, working memory and creativity are modest. Their value is simply in shifting your state.

• 04

  Low-level white noise improves learning in adults, possibly through dopamine

  An fMRI study found that low-intensity white noise improved auditory working memory, and a 54-subject study found that background noise helped as long as it wasn't too loud. A 2014 Journal of Cognitive Neuroscience paper showed white noise increasing activity in dopamine-rich midbrain areas (substantia nigra/VTA) and the right superior temporal sulcus. The idea is to raise baseline dopamine slightly, not to give yourself a 'favourite song' rush.

• 05

  White noise may harm auditory development in infants

  Work by Mike Merzenich and his student, done in young animals, found that constant white noise disrupted tonotopic maps in the auditory cortex. White noise carries no structured frequency information, unlike a voice. Huberman flags this as a reason to be cautious about running white-noise machines all night for babies, while noting the evidence comes from animals.

• 06

  Focused listening can rewire the adult auditory cortex

  Gregg Recanzone and Merzenich showed that passive listening changed little, but telling subjects to attend to specific frequencies or cues sped up learning and remapped the cortex in adults. This was some of the first evidence that adult brains can change. In practice, it means picking out particular words, keys or scales to concentrate on during each practice session.

• 07

  Balance depends on the inner ear, vision and the cerebellum working together

  The three semicircular canals detect head rotation, and the cerebellum combines that with visual and body-position information. Vision and balance drive each other, which is why standing on one leg with your eyes closed causes so much postural sway. Huberman notes that the cerebellum's non-motor outputs connect to serotonin and dopamine systems, which may partly explain why balance-heavy activities feel good.

• 08

  Leaning while accelerating trains the vestibular system best

  The vestibular system responds to acceleration and head tilt, not just position. Moving forward while tilted relative to gravity, as in carving on a skateboard, surfboard or snowboard or leaning a bike into a turn, challenges it in a way that staying upright, or even balancing on a gym ball, doesn't.