Pressed for time perception

Photo by Flickr user ToniVC. Click for sourceEdge has an interesting article by neuroscientist David Eagleman on the perception of time that describes how we can experience temporal illusions just like we experience visual illusions.

I have to say, the piece is a little wordy, so it needs a bit of concentration, but it is well worth the effort.

This section has an interesting way of fooling ourselves into perceiving an event before you seem to have triggered it:

It has been shown that the brain constantly recalibrates its expectations about arrival times. And it does so by starting with a single, simple assumption: if it sends out a motor act (such as a clap of the hands), all the feedback should be assumed to be simultaneous and any delays should be adjusted until simultaneity is perceived.

In other words, the best way to predict the expected relative timing of incoming signals is to interact with the world: each time you kick or touch or knock on something, your brain makes the assumption that the sound, sight, and touch are simultaneous.

While this is a normally adaptive mechanism, we have discovered a strange consequence of it: Imagine that every time you press a key, you cause a brief flash of light. Now imagine we sneakily inject a tiny delay (say, two hundred milliseconds) between your key-press and the subsequent flash. You may not even be aware of the small, extra delay.

However, if we suddenly remove the delay, you will now believe that the flash occurred before your key-press, an illusory reversal of action and sensation. Your brain tells you this, of course, because it has adjusted to the timing of the delay.

If you’re wanting more on time perception, TED have just released an interesting lecture by Philip Zimbardo on how we reason about time.

And rather coincidentally, Eagleman is interviewed on ABC Radio National’s All in the Mind this week, about his synaesthesia research and fiction writing.

Link to Edge article on time perception.
Link to TED on reasoning about time (thanks Patricio!).
Link to AITM interview with David Eagleman.

One Comment

  1. Viktor
    Posted June 25, 2009 at 12:16 pm | Permalink

    Does anyone know the reference to the paper in which they showed this effect of illusory reversal of action and sensation (perceiving the flash before executing the action of pressing the key)?
    Thanks.


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