A new study published in the journal PLoS One suggests that yawning could be contagious depending on how well you know the person rather than how tired you are.
The study was conducted by researchers from the University of Pisa who observed around 109 men and women and divided them into two groups of "triggers" and "observers". The "trigger" group was responsible for instigating the yawns while the "observer" group responded by yawns of their own.
The researchers recorded over 480 yawns within the first three minutes after the instigating yawn by the "trigger" group and found that people were more likely to respond to the yawn if they knew the person.
"Our results demonstrate that yawn contagion is primarily driven by the emotional closeness between individuals and not by other variables, such as gender and nationality. Related individuals showed the greatest contagion, in terms of both occurrence of yawning and frequency of yawns", the researchers wrote in their report.