Did your temperature drop a bit looking at that picture above? If so, then research out of the University of Sussex in the UK could have the reason why. According to a team of researchers, simply looking at someone visibly experiencing cold is enough to drop the body temperature of the viewer significantly.

The research carried out at the Brighton and Sussex Medical School saw 36 volunteers watch eight three-minute videos of people submerging their hands in containers of water that was visibly hot or cold. Four videos showing hands in front of the water were also used as control videos.

While viewing the videos, the temperature of the volunteers' hands was monitored and revealed their hands became significantly colder when viewing the cold water videos, indicating a "temperature contagion" was taking place. However, no change was recorded when viewing the warm water videos.

The research was led by neuropsychiatrist Dr Neil Harrison, who suggested that such unconscious physiological changes could help humans empathize with one another.

"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," Harrison says. "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 empathize with each other and predict one another's thoughts, feelings and motivations."

Looking to explain why the effect was only produced for the cold water videos and not the hot, Harrison appears to lay some of the blame at the feet of the director of the videos.

"We think that this is probably because the warm videos were less potent," says Harrison. "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). There is also some evidence to suggest that people may be more sensitive to others appearing cold than hot."

The results of the study appear in the journal PLOS ONE.