In the late 1990s I was contacted by a widow who wanted to know whether there was a scientific explanation for some unusual experiences of her late husband. It seemed that whenever he witnessed someone injure themselves, or show sudden pain, he would involuntarily experience immediate and often excruciating pain in the same body part. Thus if his wife accidentally hit her thumb while hammering, he would call out: “Don’t do that, it really hurts”. He really felt it, she said.
After what were probably one or more strokes he became extremely sensitive to touch. Even the slightest hand contact gave him the impression of sharp fingernails. However, if anyone merely commented that she had knocked her finger there was no such empathic experience of pain.
Around this time were the first reports of mirror neuron functions. Initially described in the ventral premotor region of monkeys, these nerve cells not only became activated when the animal grasped or manipulated an object but also when it saw another individual making similar actions. Thus these “mirror neurons” seemed to represent a system that matches observed events to similar, internally generated actions, thereby forming a link between observer and action.
Since those early days, this concept has been fruitfully invoked in explaining the acquisition of skills in primates by observation, and the...