Yawns are contagious because your brain is hardwired to mirror the actions of others.

Contagious yawning is a documented phenomenon known as echophenomena, which is the automatic imitation of another person's words or actions. Research published in the journal 'Current Biology' in 2017 by scientists at the University of Nottingham suggests that the urge to yawn is driven by the primary motor cortex. This area of the brain is responsible for motor function and is influenced by mirror neurons that fire during observation.Mirror neurons were first discovered in the 1990s by researchers at the University of Parma, including Giacomo Rizzolatti. These neurons allow the brain to map the actions of others onto its own motor representations. In the context of yawning, this neural activity creates a 'motor mimicry' that is difficult to suppress. Studies show that attempting to resist a contagious yawn actually increases the urge to do so.The social aspect of this behavior is significant, as contagious yawning typically begins around age four or five when children develop social cognitive skills. A 2010 study from the University of Connecticut found that children with autism, who may have difficulty with social cues, are less likely to catch yawns. This supports the theory that contagious yawning is a measure of empathy and social bonding within a group.Furthermore, research indicates that the strength of the bond between individuals affects the likelihood of the response. You are statistically more likely to catch a yawn from a spouse or close friend than from a distant acquaintance. This suggests that the brain's mirroring system is finely tuned to the emotional relevance of the person being observed.