Libet plays ball

Recent research at UCL provides corroboration for the claim that elite sports players often feel they have plenty of time to think about how they address a ball which is actually coming at them so fast that normal human beings probably shouldn’t even see it.

This effect, a perceived slowing down of time, is the kind of thing which I think would once have been shrugged off as unresearchable, outside the scope of proper science: how can we tell how things seem to people? These days we’re bolder, and the team in this case came up with an experiment in which some subjects were asked to tap a screen while others were merely asked to observe. Those who were asked to prepare action reported feeling the time they had available seemed longer.

The finding makes a certain obvious sense in that being granted extra mental time when a particularly crucial task is coming up is bound to be helpful. But it’s also a little puzzling: if the brain is capable of giving us more time, why doesn’t it do so routinely? It would never be a bad thing to have more time for reflection; if the facility only gets turned on in these special circumstances there must either be some downside or cost which makes the brain ration its use, or something else is wrong.

It’s not altogether implausible that revving up our mental processes might have an energy cost, or that our neurons might be able to speed up a bit only temporarily; but as always with consciousness there’s a deeper issue. Did mental processing actually speed up, or did it simply feel as if it did; or indeed, was the time merely remembered as passing more slowly? There’s an assumption here that when we are playing baseball or tennis control is fully conscious, but actually it’s far from clear that the deliberative  level of thought has much to do with it – it generally seems more a matter of gut reaction than strategic debate.

Another complicating factor is that we don’t actually perceive the passage of time directly, in the way we can observe spatial sizes. There is no speial organ devoted to measuring time, and it seems likely that if we do have to assess time (we’re pretty bad at it- try telling when two minutes have passed without looking at a clock) we pick up on several different indirect clues.

It may well be that one way the brain works out how much time has passed is by counting the number of ‘events’ it remembers and assuming that the gap between each of them is about the same. ‘Events’ would be mental ones, which explains why outwardly uneventful time may seem to pass very slowly – because we keep checking our watches or asking ourselves how much longer, so that there is a steady stream of mental acts, whereas when we’re caught up in something interesting there are none of these mental markers put down and time seems to fly.

It seems highly plausible to me that when we’re asked to prepare mentally for a given act (whether tapping the screen or hitting a perfect drive to the boundary) a sequence of this kind is set up, in which we keep asking ourselves ‘am I going to do it now?’ or ‘is it time yet?’. If that’s true the chances are the impression of having more time to react is actually an illusion, though it may reflect a genuinely improved state of readiness.

I couldn’t help reflecting that the conditions of these experiments rather resembled those in the famous series of experiments by Benjamin Libet which seemed to show that a decision to move one’s hand at a given moment had actually been taken significantly before that same decision entered consciousness. Libet’s subjects were asked to get ready to act in just the sort of way which might have led to the kind of time-dilation effect considered in the UCL research. Libet’s ingenious system for measuring the time of decision, with subjects reporting the position of a clock at the vital moment, should be fairly well proofed against subjective errors: but could it be that a sense of time slowing down caused Libet’s subjects to delay slightly in reporting their decision?

Just  a thought.