We're not talking about catching colds, as in the rhinovirus: scientists are now saying the feeling of being cold is contagious, too.
Watching somebody shiver is all it takes, according to researchers at the University of Sussex in the U.K., who asked their volunteers to watch videos of people putting their hands in cold water.
Despite watching the videos in a warm, comfortable setting, the volunteers' body temperatures dropped at the sight of others undertaking intense cold.
It's what the researchers call "temperature contagion" and, like other unconscious physiological changes that can occur, it's derived from human beings' communal nature.
"Humans are profoundly social creatures and much of humans' success results from our ability to work together in complex communities," says lead study author Dr. Neil Harrison. "This would be hard to do if we were not able to rapidly empathize with each other and predict one another's thoughts, feelings and motivations."
In Dr. Harrison's experiment, a total of 36 participants watched eight staged videos in which actors dunked their hands in water that was either visibly warm or cold.
In the meantime, the viewers' hands -- which were under temperature surveillance -- became significantly colder while the cold-water footage rolled, yet there were no changes in temperature while they watched the warm-water videos.
To explain the lack of change in temperature during the warm-water footage, Dr. Harrison says evidence suggests people are more sensitive to others appearing cold than they are to others appearing hot.
"Mimicking another person is believed to help us create an internal model of their physiological state which we can use to better understand their motivations and how they are feeling."
The study was published in PloS One.
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