Your Eyes Got Rhythm

Of all the things we could say about music, here's an unexpected one: Even if you can't follow a beat, your pupils do! That's pretty remarkable! A recent study shows that your pupils dilate more or less in response to changes in musical beats. This suggests people have an innate sense of meter which is the pattern of stronger and weaker beats in music.

Perception of a musical beat is a fundamental human ability and by age four we can detect meter. But we don't understand exactly how we do it. For example just how close do we have to pay attention or if at all to detect a beat? To help answer that question, consider that in rock music, the first beat is more important and you'd guess we'd miss it if it weren't there. But is that a learned response or is it innate?

In order to find out, researchers exposed sleeping infants to rock drum rhythms. They did respond more when the first beat was missing compared to later beats. This suggest humans are able to perceive meter at birth.

Now what about our pupils? One of the things our pupils respond to is that they dilate when we're surprised. So researchers monitored people's pupils as they listened to rock music in which the strong, first beat and weaker beats were imperceptibly dropped randomly.

They found the pupils dilated more in response to the missing beats and more so to the missing stronger first beats. Again, this suggests that people have an innate sense of hierarchical meter and musical training did not influence these results.

So, next time someone accuses you of being a bad dancer, just say, "Tell that to my pupils!"