It's not quite as powerful as Elsa's touch in the movie Frozen, but a new study shows that you can get cold just by looking at someone who's shivering.
How exactly does that work? According to neuropsychiatrist Dr. Neil Harrison, the human sympathetic reaction is so strong that when we see another person shiver, our body drops in temperature to help us understand what the other person is feeling. Harrison led this research study, which was published Dec. 31 in the open-source journal PLoS One.
"Humans are profoundly social creatures and much of humans' success results from our ability to work together in complex communities - this would be hard to do if we were not able to rapidly empathise with each other and predict one another's thoughts, feelings and motivations," Harrison said.
The study recruited 36 healthy young adults to watch videos of an actor whose right or left hand was submerged in icy water, or a video of someone putting a hand in warm water. There was also a control video in which the actor merely stood in front of a bowl of water. The researchers measured the temperature of the right and left hands of each participant as they watched the videos. The researchers found that when watching someone else put their hand in cold water, the temperature of the observer's hand actually dropped significantly. The researchers also found that there was a greater difference in the empathetic temperature response among participants who had greater levels of self-reported empathy.
There was no difference based on whether the hand submerged was a right or left hand. The researchers also found no change in the temperature of participants who watched the video that showed someone putting a hand in warm water.
"We think that this is probably because the warm videos were less potent - the only cues that the water was warm was steam at the beginning of the videos and the pink color of the actor's hand (whereas blocks of ice were clearly visible throughout the duration of the cold video)," Harrison said.
