Exploring Consciousness, Sensory Augmentation, The Lazy Susan Method of Productivity, and More

David Eagleman joins Tim Ferriss for a wide-ranging conversation on how the brain constructs reality from electrochemical signals locked in the darkness of the skull. He covers synesthesia and mnemonists, then his work on sensory substitution and addition through wearable wristbands that let deaf people hear, reduce tinnitus, and feed in entirely new senses like infrared. The discussion moves through memory and reconsolidation, his theory that dreaming exists to defend the visual cortex from takeover during nightly darkness, and the hard problem of consciousness. Eagleman also shares personal stories about his mentor Francis Crick, the seven-year struggle to publish his book Sum, his 'Lazy Susan' approach to juggling many projects, and his philosophy of Possibilianism and questioning one's own truths.

• Eagleman built a vibratory vest, later shrunk into a wristband, that lets deaf people effectively hear through their skin because the brain figures out incoming signals regardless of the route.
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• The wristband uses an illusion: stimulating two neighboring motors creates one virtual point between them, letting the device address 128 virtual points on the wrist despite few physical motors.
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• Tinnitus is reduced via bimodal stimulation, playing tones at the tinnitus frequency while buzzing the skin, teaching the brain that real external sounds get skin verification while the phantom ringing does not.
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• Memories must be reconsolidated after recall; an active memory pulled from storage is briefly vulnerable to erasure (e.g. by a head blow or protein synthesis inhibitor) before returning to long-term storage.
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• Eagleman's theory of dreaming: because the planet rotates into darkness, the visual cortex risks takeover by other senses at night, so every 90 minutes specialized circuits blast random activity into visual cortex as a defensive 'screensaver.'
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• The dream theory makes quantitative cross-species predictions: across 25 primate species, brain plasticity correlates almost perfectly with the percentage of REM sleep an animal gets.
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• Elephants appeared to break the theory but confirmed it: they get almost no REM sleep, sleep only one to two hours a night, and have excellent night vision, so their visual cortex needs no defense.
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• Eagleman's free-fall tower experiments showed time does not actually slow during danger; people just lay down denser memory, creating the illusion of slow motion when read back.
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• About three percent of the population has some form of synesthesia, and Eagleman has studied it for roughly 20 years.
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• Neosensory has 70 different projects exploring sensory addition and expansion beyond hearing applications.
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• Visible light (ROYGBIV) is less than a ten-trillionth of the electromagnetic spectrum passing through our bodies undetected.
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• Looking at ocean water in the microwave range accidentally revealed you can tell whether water is drinkable, something nobody knew before.
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• Eagleman's colleague Liz Phelps found that after September 11, both emotionally charged and mundane memories drifted equally over a year, making memory a 'myth-making machine.'
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• In a 2007 Harvard fMRI study, blindfolding subjects caused the visual system to start responding to touch and sound within just 60 minutes.
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• Eagleman collected rejection letters for his book Sum as high as the book itself, after writing it over seven years before it sold and became an international bestseller in 33 languages.
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• Sum was turned into two operas, one by Brian Eno at the Sydney Opera House and one by Max Richter at the Royal Opera House in London.
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• The persistence trick that sold Sum is called the 'Don Vaughn method,' named after a teenager who hit Eagleman from multiple angles and became his closest collaborator for 16 years.
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• Eagleman has written all his books at IHOP restaurants because of the bottomless coffee and quiet, distraction-free environment.
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