“Older readers will remember drive-in movies - often badly projected and frequently the picture and sound were a few frames out of sync. If the nervous system is a purely classical, mechanical information processor, our everyday experience ought to be a little bit like an out-of-sync drive-in movie... but it isn’t and why it’s not is a bit of a mystery. If you step on a sharp tack with your bare foot, the pain signal takes roughly a half second to travel 1.5-2 meters between your foot and your brain for you to become aware of it. Each nerve cell in a long chain has to receive a chemical signal, fire, release its own neurotransmitters, and so on. However, other signals, such as the sight of your foot hitting the floor, have a much shorter ‘flight time’ since light travels much faster from your foot to your eye than that chemical-electric pain signal travelling up your whole body. But if you watch your right foot as you are walking, you feel the sensation of your big toe touch the floor at exactly the same time as you see it visually. Why?
To explain how we don’t experience life like a drive-in movie, neuroscientist Benjamin Libet argued that some process in the brain ‘antedates’ our conscious experience relative to the stimulus so that multiple sensations can match up and be felt as synchronous - sort of like taking separate video and audio tracks in a video editing program and sliding one to the side so the visual component synch up with the audio. But since, it was assumed, you can’t slide the slower of these components (e.g. the pain sensation) to the right in your timeline, synching things up meant sliding all the faster signals to the left or holding them in some sort of buffer while the slower ones caught up. Libet concluded that the coherence of our experience, the fact that it is all synchronized, reflects the remarkable fact that we are really living always about a half second in the past.
It gets even stranger, though, when you include our feeling of conscious will in this fictitious synchronization. In 1983, Libet conducted a now-famous experiment that compared the subjective timing of participants’ decisions to move a finger with their motor nerves’ preparation to fire. He found that neurons begin to build up a charge a fifth of a second (200 milliseconds) before the decision to move is consciously made. This discrepancy between what is called the nerve’s readiness potential and the subjective sense of conscious will flies in the face of our ordinary experience of deciding to act and then acting, the intuitive sense that our will causes our actions and is not merely a spectator.... Libet... felt his discovery did not eliminate conscious will but altered its essential character. Instead of exerting free will, he said, we exert a veto power over pre-initiated actions. V.S. Ramachandran has called this ‘free won’t.’ Our conscious will can intercede within the 200-millisecond window to say ‘no’ to an impulsive action initiated by the brain.”
Eric Wargo, Time Loops: Precognition, Retrocausation, and the Unconscious, p.165-167. 2018 Anomalist Books.
