Does physical warmth engender psychological warmth?
The same words often describe the physical world and the emotional one. A rock or a person can be "warm," even if the meaning is quite different. In one case, it's about temperature, and in the other, it's about how this person relates to others. So why did scientists just find that holding (but not even drinking) a warm cup of coffee make us see another personality as warmer?
We frequently transfer terms from the physical world to the psychological one, says Lawrence Williams, an assistant professor of business at the University of Colorado, who was first author on a new study of physical and psychological warmth. People may be described as "cold" or "distant," "hard-hearted" or "unbending." They may make "acidic" remarks, or have a "sweet" disposition.
In recent years, psychologists have found a surprising crosstalk between the physical and the psychological realms. For example, John Bargh and colleagues at Yale University have found that people are more likely to judge others as combative and argumentative after they have assembled a jigsaw puzzle whose pieces have a sandpapery texture.
Bargh has also found that job candidates are deemed more likely to work hard by people who have held a heavy clipboard rather than a light one. "These subtle, simple aspects of the physical world seem to be capable of pushing judgments or opinions in meaningful ways," says Williams, Bargh's former graduate student. "These experiments demonstrate the power of the physical environment to shape people's mental state at the moment."
Hot on the trail?
In an experiment just published in Science, Williams and Bargh had experimental subjects hold a cup of hot or ice coffee for a few seconds, as a favor for the experimenter's assistant. About five minutes later, the subjects read about a fictitious person that listed such characteristics as "cautious," "determined" or "industrious." The brief write-up excluded traits related to a warm or cold personality.
• Five traits related to a warm or cold personality, such as "generous," "sociable," or "good-natured."
• Five traits not related to personal warmth, such as "honest," "attractive," or "strong."
You can tell where this is going: you would not be reading this if the research found no relation between the temperature of the coffee cup and the rating of the imaginary person. Instead, Williams says, "We found that the participants who had recently held the warm coffee cup rated the person as being warmer, more generous, more sociable and more caring, compared to people who'd held the ice coffee."
No difference appeared in the traits that were not related to a warm personality.
The findings fit nicely with previous studies showing, for example, how physical closeness affects the feeling of psychological closeness, Williams says, and reinforces the strong relation between the physical and the psychological realms. "It is not just haphazard that we talk about warmth in the temperature of an object, and in a personality."
Brain studies suggest one possible reason for this overlap, Williams says, since a brain region called the insula is activated when we evaluate the warmth of both objects and people. But physical and psychological warmth are also related during early experience. A warm temperature "recalls the feeling of psychological warmth that co-occurred with the sensation of physical warmth in childhood," says Williams. "When people are learning about love, affection, comfort, shelter, they have the experience of a physically warm object -- another human being."
Fifty years ago, psychologist Harry Harlow raised baby monkeys with an artificial substitute for their mothers. Those monkeys who could cling a cloth mother surrogate -- a fancy term for a mother doll -- matured into far better psychological health than the poor monkeys who clung desperately to a "mother" made of wire.
Harlow's studies proved something we today take for granted but that was heresy in the psychology business back in the 1950s: mother's presence is crucial to normal primate development. But in emphasizing the softness of the cloth mother, scientists have tended to overlook a second factor, Williams says. "The cloth mother was a source of heat, there was a light bulb directly behind her," while the wire monkey was heated by an overhead bulb. This internal warmth probably helped make the cloth surrogate mother more comforting and realistic, Williams adds, reinforcing the primacy of warmth in social relations.
Although the precise source, or sources, of the relationship between physical and psychological warmth is not definitively known, "It's pretty clear that for us to obtain the effects we did, the association has to be in the mind somewhere," Williams says. "Would we have this concept of psychological warmth if we did not have the concept about something being warm to the touch?"
- David Tenenbaum
• "Experiencing Physical Warmth Promotes Interpersonal Warmth," by Lawrence Williams and John Bargh, Science, Oct. 24, 2008.
• Love At Goon Park: Harry Harlow and the Science of Affection, Deborah Blum, Berkeley Trade, 2004.