A study led by Dr Carolyn McGettigan, from the Department of Psychology, recorded the brain responses of participants as they listened to the same people produce genuine laughter, caused by watching funny YouTube videos, and forced laughter. The participants, who were unaware the study was about laughter perception, demonstrated different neurological responses when they heard false laughter. This suggested that our brains not only distinguish between the two types of laughter, but attempt to work out why the fake laughter is not genuine.
Read the article from NeuroScientistNews (and find a link to the full text journal article) here: Fake Laughter Doesn't Fool the Brain