Remember the last time you gave your best poker face at your weekly game with the guys? Or perhaps the last time you lied about your age?
The position of your eyes foiled your attempts, according to a new study.
In the study, University of Melbourne researchers asked 12 right-handed male participants to state a series of random numbers between 1 and 30 while paced by an electronic metronome. The researchers measured their average vertical and horizontal eye position during the 500 millisecond intervals between numbers.
The researchers found three things:
- A leftward and downward change in eye position indicated that the next number would be smaller than the last.
- A rightward and upward change in eye position forecast that the next number would be larger.
- The degree of eye movement reflected the size of the numerical shift.
That means researchers were able to reliably predict the next chosen number — before it was spoken.
The lead author of the study, Tobias Loetscher, said in a statement that eye position offers insight into the nature of the systematic choices made by the brain’s random number generator.
“When we think of numbers we automatically code them in space, with smaller number falling to the left and larger numbers to the right,” Loetscher said. “That is, we think of them along a left-to-right oriented mental number line — often without even noticing this number-space association ourselves.”
Our eye movements correspond to that visualization. Are the eyes windows to the mind? In a way, yes.
“We suggest that when we navigate through mental representations — as for example numbers — we re-use brain processes that primarily evolved for interacting and navigating in the outside world,” he said.
Their results were published online in the journal Current Biology.
