Volunteers were asked to hold a hot cup of coffee
If you want someone to warm to you give them a steaming hot drink, say US researchers.
People are more likely to judge strangers as welcoming and trustworthy when they are holding a hot cup of coffee, experiments show.
Volunteers rated people as 11% "warmer" after holding a hot drink than after holding a cold drink, the study in Science reports.
The warmth of a drink also influenced how selfish participants were.
In one test 41 volunteers were tricked into holding a drink while they were being taken from the lobby to the laboratory.
They were then asked to read about a fictional character and rate how cold or warm they found them on a scale of one to seven.
Those who had held the hot drink were significantly more likely to rate the character as a warm person.
But the warmth of the drink had no impact on how the participants judged other personality traits.
In a second study, 53 people were asked to hold heated or frozen therapeutic pads believing they were evaluating a medical product.
Once they had completed a questionnaire about the pads they were offered a choice of a drink for themselves or a voucher they could give to a friend.
Those primed with coldness were more likely to choose a gift for themselves, while those primed with warmth were more likely to choose the gift for a friend.
It is not the first time temperature has been linked with emotion - a recent study found that people who were lonely reported feeling colder.
The researchers said the findings suggests that saying that someone is warm is not just a simple metaphor but a literal description of emotions such as 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 psychology Professor John Bargh from Yale University.
"These terms implicitly tap into the primitive experience of what it means to be warm and cold."
He added 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.
Dr Simon Moore, lecturer in psychology at London Metropolitan University said similar results had been shown in other types of experiments.
For example people asked to memorise a list of words will rate the experience more positively if they are given "warm" words.
"It's basic conditioning - warm sensations are nicer than cold sensations and if you feel something nice you transpose it on to something else."
He added: "It would be interesting to test someone's personality first - I would think the more suggestible they are the greater the effect of the warm cup or cold cup."
UK research done for the National Lottery has found that friendships may be the key to happiness.
People with at least 10 close friends are likely to be happier than those with fewer than five.