Asked by: Adam Soanes, Sherborne
It is probably a manifestation of our natural self-grooming behaviour. Our ape relatives constantly examine themselves and each other for ticks, dirt and small wounds, and any deviation from the normal contour of the body invites deeper scrutiny. The mild pain associated with picking a scab also releases endorphins, which can act as a reward.
Scab picking, like many grooming behaviours, is also a displacement activity that can help to distract us when we are bored, stressed or anxious. Those who suffer from obsessive-compulsive disorder (OCD) may find it hard to stop picking even when it is unsightly or causes further injury.
Read more:
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.
Authors
Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.
