I remember being in a psychology class in college and being warned (quite seriously) by the professor to never yawn in his class.
He found it insulting, irritating and said it caused others to start it too -- that it was actually contagious.
I sat high up in the auditorium (my usual spot in college anyway) to make sure if I did yawn, I didn't get called out. He certainly called out the students he saw yawning.
His classes were interesting but didn't end until 10 p.m. when most students were finishing out four hours of classes, after a long work day that generally started at 8 a.m. Yawns happen after a 14-hour day.
He was right about contagion, though. Ever watch someone yawn and find yourself yawning a few seconds later? Are you yawning now, just reading this?
Something else that has a scientific basis is the fact that itching is also contagious. When hearing stories of hives, we often end up scratching our own skin. When we see someone itching, it causes us to mimic the actions.
Do you have an itch somewhere and then end up itching a large part of your body because everything ends up feeling like it desperately needs a scratch? That's the contagious part of itching !
A psychologist named Henning Holle from the University of Hull in England asked 51 adults to watch a video of people scratching themselves and another of them tapping themselves on various body parts. The researcher, Henning Holle, asked these adults to watch a series of images that tested the following personality traits: openness, conscientiousness, extroversion, agreeableness and neuroticism.
An imaging system was used to see how the brain reacted, by monitoring blood flow to the brain. Two-thirds started scratching themselves upon watching the scratching video.
Holle wanted to know why this was happening. According to the NBC article that wrote about this story, "...watching an itch sparks activity in the anterior insular, primary somatosensory area, and the prefrontal and premotor cortices.