Summary
Neuroscientist David Eagleman explores consciousness, sensory augmentation, and the brain's remarkable plasticity. He discusses his work on improving hearing through a wristband that translates sound into vibrotactile patterns on the skin, the phenomenon of synesthesia, and how novelty can subjectively stretch the perception of time. The conversation also covers dreaming, the "Lazy Susan" method of extraordinary productivity, and lessons from titans of science.
Key Points
- Sensory augmentation technology - improving hearing through a wristband
- How the brain can learn to interpret new sensory channels
- Synesthesia and what it reveals about brain organization
- Stretching time perception through novelty
- The neuroscience of dreaming and consciousness
- The "Lazy Susan" method for extraordinary productivity
Key Moments
The sensory substitution vest: deaf people learn to hear through vibrations on skin
David Eagleman describes building a vest with vibratory motors that captures sound and converts it into patterns of vibration on the skin, from high to low frequency, exactly as the inner ear does. Deaf people trained on it can learn to hear through their skin because the brain does not care how information arrives. It makes correlations with other senses to decode the signal. Eagleman then shrunk the technology to a wristband using 128 virtual stimulation points.
"And so what we did is we built a vest that had vibratory motors on it. And this was for people who are deaf. It can capture sound and turn the sound into patterns of vibration on the skin from high to low frequency, which is exactly what the inner ear does."
Infrared on your wrist: feeling security cameras and which cars just parked
Eagleman describes wearing an infrared sensor on his wrist that lets him perceive heat signatures. Walking through a parking lot, he can instantly tell which cars have been parked a while versus recently arrived. In a library, he could feel which chairs had been sat in recently and which books had been handled. He explains that humans see less than a ten-trillionth of the electromagnetic spectrum, and there are likely Nobel Prizes hidden in the ranges we cannot perceive.
"we see such a tiny fraction of what is happening out there."
Why we dream: the visual cortex fights off takeover every 90 minutes
Eagleman presents his hypothesis that dreaming exists because of brain plasticity and the rotation of the planet. Since we spend half our evolutionary time in darkness, the visual cortex is at risk of being taken over by other senses. Harvard research showed takeover begins in just 60 minutes of blindfolding. Every 90 minutes during sleep, specialized circuits blast random activity into the visual cortex to defend its territory. This explains why blind people dream in touch and sound rather than vision, and why REM sleep correlates perfectly with brain plasticity across 25 primate species.
"in 60 minutes, the visual system started responding to touch and to sound."
