BIOLOGY BASICS

Why do our bodies do the things they do?

This week: Why we laugh WE DON’T just laugh because we find something funny, says Professor Sophie Scott, a neuroscientist at University College London. ‘We mostly laugh for social reasons and for making and maintaining social bonds. We tend to laugh more with people we like and love, and it’s a way of showing how well we understand each other.’ Brain scans have found that laughter originates in the most primal part of our brains, the limbic system, which regulates basic functions including thirst, appetite and sleep. If there is damage to the parts of the brain involving laughter — from conditions such as motor neurone disease, Alzheimer’s, Parkinson’s disease, stroke or a traumatic brain injury — it can lead to a nervous system disorder called pseudobulbar affect, which makes it hard to control laughter.