There's nothing worse than watching someone plunge into an ice-cold pool. They resurface, shivering, and - despite being pretty cosy yourself - you begin to shiver too.
This is because, much like yawning, feeling the cold is contagious.
Scientists found that 'temperature contagion' is a real process whereby our bodies drop in temperature when we watch another person become cold, which could explain the reason why sometimes we don't feel the need to put a jacket on until everybody else does.
Researchers monitored a group of 36 healthy participants (aged between 22 and 31).
The participants were asked to rate eight purpose-made videos, which depicted actors placing either their right or left hand in visibly warm or visibly cold water.
While they watched the videos, the temperature of each participant's hand was measured.
The findings, published in the journal Plos One, revealed that those who rated the videos showing hands immersed in cold water became significantly cooler than those showing hands placed in warm water.
Scientists suggest that during social interactions, we synchronise our physiological (and behavioural) responses with others. This then enables us to gain emotional understanding and group coherence through inter-subjectivity.
In other words, we empathise with the person who is cold and shivering - and then we begin to mimic them.
The theory of temperature contagion follows on from a previous study, published in 1993 by the American Psychological Society, which discusses 'emotional contagions'.
This refers to the process of the human body automatically mimicking and synchronising "expressions, vocalisations, postures and movements" with those of another person. Other activities believed to be emotional contagions are loneliness, laughter and stress.
Neuroscientist Neil Harrison, from the University of Sussex, said: "We believe that this mimicry of people's bodily response helps us understand how they are feeling."
"Mimicking another person is believed to help us create an internal model of their physiological state which we can use to better understand their motivations and how they are feeling."
[H/T Telegraph]