Yelp If It Hurts

Why do human beings yelp when they are in pain? Could such screams have any evolutionary benefit? In the past, some scientists have suggested that we have evolved to spontaneously shout out in order to warn others of danger. But according to a new study, we scream because it helps us distract ourselves from feeling pain. The researchers claim that whenever we shout ‘ow’, it interferes with pain messages travelling to the brain.

The study was conducted by researchers from the departments of psychology and neurobiology at the National University of Singapore and published in Journal of Pain. According to the researchers, such expressions of pain are shared across language barriers. While those who speak in English say ‘ow’ or ‘ouch’, Italians say ‘ahia’, Chinese say ‘aiyo’, and South Africans yell ‘eina’.

For the study, 56 participants were asked to immerse their hands in painfully cold water. The scientists tracked how long the participants could keep their hands immersed in the water. In one test, the volunteers were allowed to shout ‘ow’ when they felt pain. The experiment was then repeated four more times with the volunteers asked to stay silent. In one such test, they could press a button when they felt pain. In another, they were played a recording of themselves shouting ‘ow’. In yet another test, the recording was of another person shouting ‘ow’. And in the last test, they were made to sit passively until they could no longer withstand the pain.

The researchers found that when participants shouted out, they were able to stand the pain for the longest duration. They managed nearly 30 seconds on average, five seconds more than when they were told to sit and do nothing. Hearing recordings of their yelps or those uttered by someone else did not increase their capacity for pain. According to the researchers, the muscle movements involved in making such an exclamation interferes with the pain messages travelling to the brain. The researchers write in the journal: ‘Together, these results provide first evidence that vocalizing helps individuals cope with pain. Moreover, they suggest that motor more than other processes contribute to this effect.’

Human brainpain messagespain toleranceScreaming