In monkeys, pupil size linked to perception of milliseconds
The eyes may reveal whether the brain’s internal stopwatch runs fast or slow. Pupil size predicted whether a monkey would over- or underestimate a second, scientists report in the Nov. 2 Journal of Neuroscience.
Scientists knew that pupils get bigger when a person is paying attention. They also knew that paying attention can influence how people perceive the passage of time. Using monkeys, the new study links pupil size and timing directly. “What they’ve done here is connect those dots,” says neuroscientist Thalia Wheatley of Dartmouth College. More generally, the study shows how the eyes are windows into how the brain operates. “There’s so much information coming out of the eyes,” Wheatley says.