Researchers from Yale University, Connecticut conducted experiments that showed that people perceive others as more generous and more attentive if they have just been holding a hot cup of coffee, and that the inverse is true for cold drinks.
A second study found that people are more likely to give something to others if they held something warm, and more likely take something for themselves if they held something cold.
In the study, published in the current issue of the journal Science, the research team built on earlier studies that show the physical distance between individuals also influence social judgment about others.
The experiment suggests that the warmth of an object or the distance that is felt between people amounts to more than simple metaphors. Both instances, researchers said, are literal examples of trust first experienced between mother and child during infancy.
"When we ask whether someone is a warm person or cold person, they both have a temperature of 98.6 (Farenheit, 37 Celsius)," said Yale psychology professor John Bargh, who co-authored the study with Lawrence Williams at the University of Colorado.
"These terms implicitly tap into the primitive experience of what it means to be warm and cold."
Physical temperatures affect not just how humans see each other, but also how humans behave, said Bargh, adding that the power of temperature on character assessments has been backed up by recent brain imaging studies.
"Physical warmth can make us see others as warmer people, but also cause us to be warmer, more generous and trusting as well," he said.
The study was funded by the National Institutes of Health.