Paula Croxson Ph.D.

Selective Memory

Mirror, Mirror

Does mirroring another person’s actions make you more socially aware?

Posted May 22, 2012

Did you accidentally catch someone’s eye on your way to work this morning? And, if they smiled at you, did you find yourself automatically smiling back? The chances are, you did—it’s hard to resist. Maybe you also felt as if you knew something about what that person was thinking—they’re happy, or friendly; perhaps you even found yourself liking them.

How do we understand others’ actions and intentions so easily? Sometimes it’s called “the problem of other minds”, and the problem is this: if I only have access to what’s going on in my own mind, how can I understand the minds of other people? It could be a key part of disorders such as autism, where people seem to have trouble understanding others’ state of mind.

One reason we humans are so good as this may lie in the parietal and premotor cortex of the brain, two regions which receive a lot of information from the rest of the brain and have the connections to influence our actions.

These regions are remarkable because they contain neurons that have the potential to give us access to the minds of others. They are called mirror neurons, because they quite literally mirror someone else’s actions. When someone you are speaking to yawns, and you feel an irresistible urge to yawn as well, it may be that seeing them yawn activated your mirror neurons, which are directly wired into your motor system, driving your own facial muscles.

In fact, mirror neurons are active both when you are watching someone else perform an action and when performing the action yourself. This suggests that these cells provide a link between watching and doing, and might be the route to learning actions by observation and mimicry, or copying. Monkeys have them too. Even more convincingly, the same neuron in the brain of a monkey is active for watching and performing one particular action. So if the monkey is watching another monkey grab a banana, or grabbing the banana itself, the same mirror neuron fires.

If you think about it, this is powerful stuff. These neurons might allow us to do more than “monkey see, monkey do”. They might also provide a neural basis for empathy. Mirror neurons could give us a window into others’ emotions. When your own mirror neurons fire in synchrony with the other person’s movement, you may actually have the experience of knowing what they are intending to do – what their goal is.

A study in the Journal of Neuroscience by Jeremy Hogeveen and Sukhinder Obhi at the University of Ontario investigated whether the mirror neuron system is primed by social interaction. In other words, are our mirror neurons more active if we have just come from a social setting?

They didn’t try to measure something as abstract as empathy; instead they measured a barely-perceptible muscle twitch caused by transcranial magnetic stimulation (TMS). TMS uses a brief pulse of electromagnetism to activate a small area of the brain – in this case the motor cortex that controls hand movements. When they sent a TMS pulse into the motor cortex, it caused the muscles in the hand to twitch imperceptibly, but in a way that could be detected with electrodes.

The idea was, if seeing someone else perform an action excited the mirror neuron system, they would cause the motor cortex to also become more excited, and the muscle twitch would be bigger. The more active the mirror neurons, the bigger the twitch. It’s a clever way to measure the action of neurons in the human brain without sticking an electrode in there.

Hogeveen and Obhi found that the twitch was bigger if the participant had been taking part in a social interaction with an experimenter beforehand, and even bigger if they had been mirroring the behavior of the experimenter during the conversation. This effect was also specific to movements involving humans—if a robot made the movement they watched, the muscle jump did not increase.

This cleverly-designed experiment doesn’t just show that we can prime our own ability to be empathetic with others by increasing our social interaction and mirroring other people’s actions. It also suggests that our mirror neurons are responsible for the effect. It’s worth bearing in mind, though, that no studies have yet showed that the mirror neuron system is actually active when you are mirroring others’ actions, and in this study no actual mirror neurons were recorded. But the evidence for their role in social learning is growing.