The Brain’s Now
Our perception of time raises all sorts of questions, Eagleman began. “Why
does time seem to slow down when you’re scared? And why does it seem to speed
up as you get older?”
With an onscreen demonstration, Eagleman showed that “Time is actively
constructed by the brain.“ His research has shown that there’s at least a
1/10-of-a-second lag between physical time and our visual subjective time of,
and the brain doesn’t guess ahead, it fills in behind. “Our perception of an
event depends on what happens next.” In whole-body terms, we live a
half-second in the past, which means that something which kills you quickly
(like a sniper bullet to the head), you’ll never notice.
In order to manage a realistic sense of causality, the brain has to calibrate
the rate of different signals coming into it. When that system malfunctions,
you can get “credit misattribution”—the sense that “I didn’t do that!” It may
explain why some schizophrenics think that their normal internal conversation
is voices coming from somewhere else, and it might be curable by training their
brain to manage signal lags better.
Is “now” expandable? Why do you seem to experience time in slow motion in a
sudden emergency, like an accident? Eagleman’s (terrifying) experiments show
that in fact you don’t perceive more densely, the amygdala cuts in and records
the experience more densely, so when the brain looks back at that dense record,
it thinks that time must have subjectively slowed down, but it didn’t. “Time
and memory are inseparable.”
This also explains why time seems to speed up as you age. A child experiences
endless novelty, and each summer feels like it lasted forever. But you learn
to automatize everything as you age, and novelty is reduced accordingly,
apparently speeding time up. All you have to do to feel like you‘re living
longer, with a life as rich as a child’s, is to never stop introducing novelty
in your life.
—Stewart Brand
[email protected] <mailto:[email protected]>
A linkable version of this summary is on Medium
<https://medium.com/@stewartbrand/the-brains-now-ec0440c7fcdb#.so1oezu5n>.
The video of David Eagleman’s talk may be viewed here
<http://longnow.org/seminars/02016/oct/04/brain-and-now/>; iPod version here
<https://itunes.apple.com/us/podcast/salt-seminars-about-long-term/id186908455>._______________________________________________
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