Looking to improve your romantic odds? Get your date a steaming cup of coffee.
That's the implication of a new study by researchers who wanted to see if there was any connection between physical and emotional heat.
To their surprise, they found that people who held a cup of hot coffee for 10 to 25 seconds warmed to a perfect stranger. Holding a cup of iced coffee had the opposite effect.
If you want to make a good impression, advised study author Lawrence E. Williams, a University of Colorado at Boulder assistant professor of marketing, a fresh cup of coffee "may bias the situation in your favor."
The study, to be published today in the journal Science, is the latest to show how physical properties such as distance or temperature can unconsciously influence emotional reactions. In a previous experiment, for example, people who were asked to plot remote points on a graph expressed distant feelings about relatives afterward.
"Our mental processes are not separate and detached from the body," said John A. Bargh, a Yale University psychologist and co-author of the current study.
The findings raise the potential for manipulation beyond matters of the heart. Williams said it was not hard to envision marketers using warm cookies to make connections with customers -- and prime them to buy.
By the same token, Bargh said, shoppers who want to resist pushy salespeople could improve their chances by carrying an icy can of soda in a pocket.
But when it comes to personal relationships, researchers said, a hot beverage can't always overcome awkward habits and distasteful traits.
"If I had a nice, warm cup of coffee with Adolf Hitler, I'm still not going to like him," Bargh said.
In the latest study, a lab worker asked each of 41 subjects to hold a cup of warm or iced coffee. They were then asked to rate the personality of an unidentified person whom researchers described as "skillful, industrious, determined, practical and cautious."
People who had held the warm coffee gave the stranger an average score of 4.7 on a seven-point scale, better than the average score of 4.3 from people who had held the iced coffee.
In a second experiment, a lab worker asked 53 participants to evaluate either a heated or a frozen therapeutic pad. After completing that task, the subjects were told they could choose as a reward either a cold drink or an ice cream that they could either keep for themselves or share with someone else.
Of the people who had handled the hot pad, 54% chose a reward to share with a friend, and 46% picked a reward for themselves. Among those who had touched the cold pad, 25% selected a reward meant for sharing, and 75% chose an item for themselves.
"Physical warmth can make us see others as warmer people but can also cause us to be warmer -- more generous and trusting -- as well," Bargh said.
Researchers postulated that the association between temperature and emotional warmth begins in infancy, when the physical warmth of being held is connected to food, safety and love. Later in life, a hot cup of coffee or a warm bath might activate memories of those feelings, they said.
But Piotr Winkielman, a psychology professor at UC San Diego, questioned whether the experiment actually tapped an emotional pool. Only a brain scan would reveal that, he said.
"Is there emotion involved? Or is it just a thought floating in their heads?" he asked.