In language, positive ideas are linked with the right side of space and negative ideas with the left. It's good to be 'in the right', but bad to be 'out in left field'.
In an experiment by Max Planck Institute and University of Pennsylvania where people were asked which of two products to buy, which of two job applicants to hire, or which of two alien creatures looks more intelligent, right-handers tended to choose the product, person, or creature they saw on their right, but most left-handers chose the one on their left.
Daniel Casasanto of MPI believes that people's conceptions of good and bad depend, in part, on the way they use their hands.
"People can act more fluently with their dominant hand, and come to unconsciously associate good things with their fluent side of space," he said.
To test this, Casasanto and colleagues studied how natural right-handers think about good and bad when they wore a ski glove on their right hand.
Stroke patients completed a task that reveals implicit associations between space and goodness in healthy participants. Patients who had lost the use of their left hand showed the usual right-is-good pattern. But patients who lost the use of their right hand following damage to the left-hemisphere of the brain associated good with left, like natural left-handers.
"People generally think their judgments are rational, and their concepts are stable. But if wearing a glove for a few minutes can reverse people's usual judgments about what's good and bad, perhaps the mind is more malleable than we thought," Casasanto concluded.
The study appears online March 9, 2011 in Psychological Science.