A University of Nottingham team found it occurs in a part of the brain responsible for motor function.
The primary motor cortex also plays a part in conditions such as Tourette's syndrome.
So the scientists say understanding contagious yawning could also help understand those disorders too.
Contagious yawning is a common form of echophenomena - the automatic imitation of someone else's words or actions.
Echophenomena is also seen in Tourette's, as well as in other conditions, including epilepsy and autism.
