Understanding ‘Aha!’

insight.jpgTo this day, psychologists understand little about ‘insight’ – that Eureka moment when a long-sought answer suddenly jumps to mind. These “Aha!” experiences range from the trivial – suddenly solving a crossword clue, to the profound – like Kary Mullis’s Nobel-Prize-winning invention of the polymerase chain reaction, the basis of which occurred to him while driving home one day.

According to Edward Bowden and colleagues writing in the latest issue of Trends in Cognitive Sciences, insight is achieved via the right-hemisphere (cf. Hack #69 ) which “engages in relatively coarse semantic coding, and is therefore more likely to maintain diffuse activation of alternative meanings, distant associations and solution-relevant concepts”. Unfortunately, by its nature this diffuse activation is often weak and beyond conscious reach of the struggling thinker.

In support of this they’ve shown, for example, that when people are presented with the solution to a problem they couldn’t solve, they’re quicker at reading this solution aloud when it’s presented to their left visual field (right hemisphere) than to their right visual field (left hemisphere). This suggests the right hemisphere had been closer to reaching the solution than the left. Moreover, brain scans of solutions reached by insight revealed more activity in the anterior superior temporal sulcus of the right hemisphere, than did solutions not reached by insight. So, perhaps you should do tomorrow’s Suduko while looking out of the left corner of your eyes!

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Another look at mindsight

eye.jpgLast year, psychologist Ronald Rensink at the University of British Columbia proposed that some people have an alternative mode of visual experience – one that involves sensing but not ‘seeing’ – what Rensink dubbed ‘mindsight’. Now his claims have been forcefully rebutted by Daniel Simons and colleagues who argue it’s far more mundane than that: it’s all to do with how cautious people are in deciding whether or not they’ve seen something.

Rensink had performed a kind of change blindness experiment (see Hack #40) that involved participants reporting when they spotted a subtle change between two pictures. He invited participants to press one key when they ‘sensed’ a change between the pictures and to press another key only when they could ‘see’ the change and knew where and what it was. Rensink reported in Psychological Science that a subset of participants (30 %) showed evidence of what he dubbed ‘mindsight’: on a minority of trials they would report sensing the change at least a second earlier than they reported seeing it. “This mode of perception involves a conscious (or mental) experience without an accompanying visual experience”, Rensink explained. “The results presented here point towards a new mode of perceptual processing, one that is likely to provide new perspectives on the way that we experience our world”, he said.

But in this month’s issue of Psychological Science, Daniel Simons and colleagues at the University of Illinois dismiss Rensink’s findings. “Provocative claims merit rigorous scrutiny”, they said. “We rebut the existence of a mindsight mechanism by replicating Rensink’s core findings and arguing for a more mundane explanation…”.

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Time compression

This could be a long shot, but if you’re really enjoying yourself and you don’t want time to go too fast, try keeping your eyes as still as possible. Concetta Morrone, John Ross and David Burr have just reported in Nature Neuroscience that subjective time is compressed around the onset of a saccadic eye movement. Saccades are the rapid, jerky eye movements that we perform thousands of times every day (see Hack #17) to align targets of interest with the high-acuity fovea at the centre of our eyes.

time.jpg

Morrone’s team asked participants to compare the time interval between two horizontal bars that were flashed up around the onset of a saccade, with the interval between a second pair of horizontal bars flashed up after the saccade. Participants said the intervals felt the same when the gap between the first two bars was 100ms and the gap between the second pair was 50ms – that is, subjective time was speeded up by a factor of two near the saccade onset.

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The BIG questions

question_mark_2.jpgTo celebrate its 125th anniversary, Science magazine in America has published a series of free articles counting down the 125 biggest questions facing science in the next quarter century.

In second place is: “What is the biological basis of consciousness?”. Other top-25 entries of particular interest to Mind Hackers are: “How are memories stored and retrieved?”, and “How did cooperative behaviour evolve?”.