People cooperate with each other more when they've been holding hot, as opposed to cold, objects.

This is the finding of a study by Simon Storey and Professor Lance Workman from the University of South Wales presented as part of the poster presentation session at the British Psychological Society's annual conference today, Thursday 8 May 2014, hosted at the International Convention Centre, Birmingham.

The Iterated Prisoner's Dilemma (IPD) task, designed to measure levels of cooperation, was completed by 60 students. Before performing the IPD task, participants were asked to hold either hot or cold objects.

Analysis showed that individuals who held hot objects cooperated significantly more frequently when they had held the hot, as opposed to cold, objects.

Professor Workman said: "There is evidence that, during our evolution, the part of the brain responsible for processing interpersonal warmth came to 'piggyback' on top of the part of the brain responsible for physical warmth. So when we say we have 'warmed to someone' this is, in a sense, literally true."

We used prisoner's dilemma because it is a well-established tool for measuring cooperation, but we suspect that simply by giving someone a sensation of warmth they are more likely to cooperate under other circumstances. Perhaps next time you need to ask someone for a favour it might be worth making them a cup of tea first!"

Full poster paper presentation title: 'Warm hand, warm heart: warm temperature priming increases cooperation on the Iterated Prisoner's Dilemma'.