Why people's pupils dilate when surprised - study
Scientists have found that pupil dilation upon surprise is part of an arousal response that helps the brain adapt more quickly to unexpected information. In a study of 63 participants who looked at colored spots and predicted the next color, pupils dilated when predictions were wrong. The reaction reflects a sharp surge of arousal and the brain switching to an 'update' mode.
Scientists have discovered that pupil dilation upon surprise is not merely a reaction to changes in light, but part of a broader arousal response that helps the brain adapt to unexpected events. In a study published on the Science Alert portal, 63 healthy participants were shown a sequence of colored spots and asked to remember the colors and predict the next one. When their predictions did not match the actual color, their pupils dilated. Co-author of the study, Brown University assistant professor Matt Nassar, explained that after a sudden event, the brain likely switches to an 'update' mode, and pupil dilation is one noticeable sign of this process. Researchers believe such short-term changes in the nervous system are useful for processing unexpected events. Previously, 'Cursor' reported that scientists explained how eye function changes during different stages of sleep.