QUANTA

Thursday, March 3, 2011

Decision-makers betrayed by their wide eyes

09 March 2010 by Ewen Callaway
Magazine issue 2750. Subscribe and save
For similar stories, visit the The Human Brain Topic Guide

WHY can't teachers keep a secret? Because their pupils give them away. It turns out that when people make decisions, their pupils dilate, a subtle cue that could be used to predict a person's intentions, or even converse with people with locked-in syndrome.

It is well known that pupils dilate as it gets darker, and in stressful situations as part of the "fight-or-flight" response. The reflex is mediated by the release of the hormone noradrenalin, which in animals has also been implicated in memory and decision-making. Olivia Carter, a neuroscientist at the University of Melbourne in Australia, wondered if noradrenalin - and by implication pupil dilation - might also be linked to human cognition.

To investigate, her team asked volunteers to pick one of five random digits that displayed on a monitor one after another for 2 seconds each, and to press a button indicating their choice after ...



Publisher and/or Author and/or Editor:__Andres Agostini ─ @Futuretronium at Twitter! Futuretronium Book at http://3.ly/rECc