April 11, 2002

Slicing Time More Finely

A question that I asked Rich Ivry, Director of Bekeley's Institute of Cognitive and Brain Sciences, over lunch:

"Back when I was 17, on my high school's team for the local metropolitican area quiz-show jeopardy analogue, I learned quickly that success required two things. First, you had to maintain constant pressure on the buzzer so that only the tinyest finger movement, a tenth of an inch or so, was necessary to activate the buzzer that would halt the reading of the question and give you the opportunity to answer. Second, you wanted to press the buzzer not when you knew the answer, but when you thought that the next word in the question would give you enough information to answer the question.

"During the quiz show, I could feel--I could sense--I could know--the time interval between the instant I had decided to press the buzzer and when the buzzer sounded, and I could feel--I could sense--I could know--the time interval between when the buzzer sounded and when the host stopped reading the question. Yet during my daily life I am not conscious of these time intervals. I believe that my body instantaneously does whatever I command it to do, rather than that my brain is always 1/20 or 1/10 of a second behind.

"How is it possible that I have this illusion of living in the present, rather than a fraction of a second in the past, in my normal daily life? Given that I have this illusion, how come I could override it back when I was playing 'It's Academic'?"

Rich responded that there is indeed evidence that the processed sensory input we respond to does indeed anticipate the future. Show someone a movie of a galloping horse, cut it off in mid-sequence, show them a bunch of frames, and ask them what was the last frace they saw, and people are highly likely to point to a frame that they in fact did *not* see, that was later than the last movie frame they actually saw...

Posted by DeLong at April 11, 2002 03:57 PM | TrackBack

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