In 1996, three neuroscientists were probing the brain of a macaque monkey when they stumbled across a curious cluster of cells in the premotor cortex, an area of the brain responsible for planning movements. The cluster of cells fired not only when the monkey performed an action, but likewise when the monkey saw the same action performed by someone else. The cells responded the same way whether the monkey reached out to grasp a peanut, or merely watched in envy as another monkey or a human did. Because the cells reflected the actions that the monkey observed in others, the neuroscientists named them “mirror neurons.” Later experiments confirmed the existence of mirror neurons in humans and revealed another surprise. In addition to mirroring actions, the cells reflected sensations and emotions.
“Mirror neurons suggest that we pretend to be in another person’s mental shoes,” says Marco Iacoboni, a neuroscientist at the University of California, Los Angeles School of Medicine. “In fact, with mirror neurons we do not have to pretend, we practically are in another person’s mind.”