Sci is off to the frozen north to visit people for the holidays. She'll be back very shortly, but in the meantime, here is a repost, to make us all feel a little warmer. Originally published Nov. 4, 2008

I don't know about you, but I love fall. One of the things I love most about it is enjoying hot delicious drinks (Pumpkin Spice Latte at Starbucks is the most delicious thing ever) while suggled up beneath a fleece blanket and a cat. There's just something about the chill in the air that makes you appreciate things that are warm. And when we get into winter...well you need things that warm you. You get in from the cold and wet and you're hating humanity. You need something to make you feel warmer about life. And it may be that things that make you feel warmer about life...make you feel warmer about the people in it.

Williams and Bargh. "Experiencing physical warmth promotes interpersonal warmth" Science, 2008.

I'll tell you straight up I love this study for its simplicity and elegance. Incredibly simple experiment with a clear effect, and related to the literature. I did find myself wishing for an MRI scanner, though. I'm much more a neuroscientist than a psychologist, and so hearing stuff like "warm" and "cold" without seeing changes in cranial blood flow or receptors or drug reaction feels kind of fluffy to me. But that's just me, and it really is a killer study. Who knows? Maybe the MRI is next! Here's hoping.

Everyone knows someone who has a "warm" personality. Most likely, everyone also knows someone who has a "cold" personality, and there is a huge difference between how you feel about the two individuals. The first person to decribe "warm" and "cold" personalities in first impressions of individuals was Solomon Asch in 1946 (oooh, I should do a history post on that!), and the concept has become recognized as one of the two main "first impressions" that people quickly form of other people. The other concept, by the way, is competence. These two concepts aren't just found in Western Society, either. They are the principles underly every group stereotype across dozens of countries. Warmth even appears to be more important than competence, as warmth is used to make judgements of whether or not someone is trustworthy.

Obviously, there's not one thing that you can pinpoint about someone that makes them "warm" or "cold". The concepts of warm and cold personalities in fact refer to a constellation of traits, usually related to the perceived friendliness, helpfulness, and intentions of the other person. To determine that someone is "warm" is to determine that they are a friend (or at least a "non-foe"), while someone who is cold might be perceived as being out to sabotage your actions. The second trait, competence, is then used to figure out whether or not that person is capable of doing you a good or bad turn. After all, you don't want to enlist the help of someone who is nice but completely incompetent, but at the same time, you won't waste energy defending yourself against someone who dislikes you, but acts like a total idiot and fails at sabotaging you.

So why "warm" and "cold"? Psychologists have posited that this is because you metaphorically base the personality concept on a physical sensation. This goes back to things like nurturing, where warmth is associated with trust and comfort. A good example of this used in the paper is Harlow's monkeys. These monkeys were taken away from their mothers and instead given a choice between a warm cloth surrogate or a wire surrogate. The babies prefer the cloth surrogate every time, even when it's the wire surrogate that is associated with food, implying that the warmth and softness of the cloth gives them comfort. Not only that, monkeys raised on a cloth surrogate end up relatively normally socially speaking, while monkeys raised on a wire surrogate are incapable of normal social interactions with other monkeys. So the warmth and comfort of physical contact may be as or even more important than the monkey's need for food.

Not only is this evidence in monkeys pretty compelling, but there is evidence in humans that physical and social warmth are associated. An area of the brain called the insular cortex is known to light up when the brain is processing both physical warming and psychological warmth information (pictures of mothers holding babies and stuff). And a part of the insula (the dorsal posterior part) is associated with both physical temperature and the sense of touch. The insula also lights up during feelings of trust, empathy, and things like guilt, and is definitely associated with feelings of social belonging or rejection (for more on this, check out my post on context and personality).

With all this knowledge in mind, the authors hypothesized that feelings of tactile warmth should activate concepts of interpersonal warmth. And so they conducted a test. They recruited a whole bunch of college girls to fill out a personality impression questionnaire. Each girl was met in the lobby by a student (who was blinded to the test), who had a clipboard, a whole bunch of books, and either a HOT or ICED cup of coffee. In the elevator on that way up, the loaded-down student asked the testee to hold their cup of coffee for a second while they wrote some information down on the clipboard. That was ALL they got, the testee held the hot or cold cup of coffee for just a few seconds in the elevator.

When they got to the room, the subjects were asked to rate someone's personality based on a set of adjectives. And those who had touched the HOT coffee rated someone as being "warmer" (more positively), than those who had touched the COLD coffee! It appears that touching something hot or cold really does affect how you perceive the world and people around you.

To follow up this study, they did the same thing with another group of girls. This time, instead of a cup of coffee, the subjects did a "product" test of hot or cold therapeutic pads. Then they were told they got a gift for participating. They could choose a gift for themselves, or a gift certificate to "share with a friend". Just to double blind everything, they also referred to the gift certificate for themselves, or a gift with a friend, so each one was associated with either a "selfish" or "sharing" condition. And the girls who had touched the hot pads were more likely to choose the gift associated with "sharing" than those who had touched cold pads!

If you really think about this study, it gives you a really cool "wow" moment of how closely your mind is connected to the physical world around you. And it's got practical applications, too! Feeling grouchy and unconnected to the extended family this year? Have a hot cup of tea. You'll feel better, really. :)

L. E. Williams, J. A. Bargh (2008). Experiencing Physical Warmth Promotes Interpersonal Warmth Science, 322 (5901), 606-607 DOI: 10.1126/science.1162548