Fear fosters flight: a mechanism for fear contagion when perceiving emotion expressed by a whole body.

Darwin regarded emotions as predispositions to act adaptively, thereby suggesting that characteristic body movements are associated with each emotional state. To this date, investigations of emotional cognition have predominantly concentrated on processes associated with viewing facial expressions. However, expressive body movements may be just as important for understanding the neurobiology of emotional behavior. Here, we used functional MRI to clarify how the brain recognizes happiness or fear expressed by a whole body. Our results indicate that observing fearful body expressions produces increased activity in brain areas narrowly associated with emotional processes and that this emotion-related activity occurs together with activation of areas linked with representation of action and movement. The mechanism of fear contagion hereby suggested may automatically prepare the brain for action.