Just looking at someone who is probably very cold is enough to make your own body temperature drop a little, according to a new study in PLOS ONE led by Neil Harrison, a neuropsychiatrist at the Brighton and Sussex Medical School, because releasing a study on how to feel even colder seems super useful in the dead of winter. Cruelly, according to Harrison’s findings, the effect doesn’t work the other way around: Feeling cold is contagious but feeling warm is apparently not. (But that could be more about the study design — we will get to that.)
Harrison measured the temperatures of the right and left hands of 36 volunteers, and then made them watch a short video which showed one of four scenes: either an actor adding hot water from a steaming tea kettle into a transparent container filled with water, and then placing his right or left hand into the water; or an actor dumping ice from a plastic bag into the container and then placing a hand into the water. (Two additional, neutral scenes showed the actor’s right or left hand simply resting in the container of water.) In all of the videos, only the actor’s hand was shown, so the volunteers couldn’t see their facial reactions.
After they’d watched the two-minute videos, Harrison once again measured the temperature of the volunteers’ hands. As he’d expected, when the study volunteers watched the actor submerge his right or left hand into the ice water, they experienced a small but significant drop in the temperature of their own corresponding hand; no significant change was measured in the hands of the people who’d watched the neutral scenes.
But the experimenters were also unable to find a measurable difference in the temperature of the hands of the volunteers who’d watched the actor dunk his hand into the hot water, an effect that, Harrison acknowledges in the paper, could be explained by the way the video was set up: In the ice cube video, the ice cubes remained for the duration of the two-minute clip, giving viewers a visible reminder of the cold. In the tea kettle version, on the other hand, the video starts with the visual cue of the steam, but, apart from the actor’s slightly pinker hand, there wasn’t anything observable that shouted Hot! to the viewer once the water was poured. Or, maybe, Harrison says in the press release, there’s another explanation: “There is some evidence to suggest that people may be more sensitive to others appearing cold than hot.” Perhaps feeling cold is just a vicious, contagious, frozen circle.