THURSDAY, Oct. 23 (Health.com) — It's an old saying that cold hands equal a warm heart. But a new study suggests you're better off giving a warm handshake to someone you're trying to impress.
People who have their hands warmed—for example, by holding a cup of hot coffee—are kinder and more generous toward others and view other people in a more flattering light than they do after holding an icy-cold beverage, according to a study in Science.
Don't laugh. Although it seems like a deceptively simple—even silly—finding, the researchers say the study sheds light on a part of the brain known as the insula, which registers temperature and feelings of trust and empathy, as well as social emotions like guilt or embarrassment.
Our brains may be hardwired during infancy to associate warmth with trustworthiness, says John Bargh, PhD, a professor of psychology at Yale University who conducted the study with Lawrence Williams, PhD, from the University of Colorado.
"We have this almost direct connection in our brain between touching and physical temperature and trust in other people," he says.
That connection was probably forged during infancy, or even during evolution, when having a tight bond to a caregiver could have been the difference between life and death.
"When you're tiny and helpless, the ones that keep close to food-giving and warmth-giving and shelter-giving caretakers survive, and the ones who don't, do not," he says.
And when something goes wrong with the insula, it may affect the way we interact with others. There's some research to suggest this happens in people with borderline personality disorder, a type of mental illness, Bargh explains.
"They can’t deal with anyone else, they don’t know who to trust, and they trust the wrong people," he says.
In the study, a researcher met volunteers in the lobby of a building. During the elevator ride, the researcher asked them to briefly hold a drink—either hot or cold—so that he could write on a clipboard.
After they arrived in the laboratory, the 41 volunteers read a passage about "person A" and rated his personality traits. Compared with those who held a cold drink, warm-drink holders tended to rate "person A" as having a warmer personality.
In the second study, 53 volunteers were asked to rate a cold or hot therapeutic pack. Then they were given a choice: They could choose a Snapple for themselves or a $1 gift certificate for ice cream for a friend (and vice versa, depending on the group). If the pack was cold, 75% of the volunteers kept the gift for themselves. If it was warm, only 46% opted to keep the gift rather than give it away.
"It would be all too easy to laugh this off and say this is ridiculous," says Susan Fiske, PhD, a professor of psychiatry at Princeton University who has studied warmth in personal interactions. "But the point they are making is very serious science. They have done their homework; they have conducted really rigorous research, even though it's couched in everyday terms."
The researchers were studying a "priming effect," which is exposure to an object that then influences behavior. Priming people to something—such as an American flag—can change the way they vote, as can voting in a school versus voting in a church.
The study adds to evidence that these subtle social cues can also affect the way we feel about other people, Fiske says. For example, research has shown that subtle mimicry of body language—for example, an interviewer crosses his arms and you cross your arms too—creates good feelings and trust as well as a higher rating for the mimicker.
These cues are all part of a "friend-or-foe" decision that we make when we meet new people, says Fiske. "Is this person or entity with me or against me? It's really a fundamental survival response because you need to know instantly." The study suggests this is also "really important social behavior; it's not trivial," Fiske says. If you know you have a cold handshake, it's a good idea to "quickly put your hand in you pocket on the way to the interview."
However, that's not to say we are prisoners to these subtle cues—or that a cup of joe from Starbucks will catapult you to instant popularity.
"This doesn’t mean that we are totally driven by these; it’s an influence, but it's not like you're being driven around willy-nilly," says Peter Glick, PhD, a professor of psychology at Lawrence University in Appleton, Wis. "If someone likes you a little bit better, that could translate into something good, but it's not like this is the only thing that’s going on."