The discovery of mirror neurons was one of the most important psychosocial discoveries of the twentieth century. Understanding what they are and how they work is vital for anyone who wants to understand child maltreatment.
In 1992, researchers stumbled upon the discovery of mirror neurons by accident. (Pelligrino et al., 1992) The research team, led by G. di Pelligrino, was using laser-thin electrodes which could measure single brain cells to see which cells lit up during specific movements. It proved an extremely precise way to map the brain’s activity during movements. If a monkey was grasping at something, it would light up different circuitry than if the monkey was performing a similar but different action, such as tearing paper.
The real discovery came on a hot afternoon, when a research assistant returned to the lab eating an ice cream cone. It grabbed the attention of one monkey, and as our furry friend watched her eat the ice cream, scientists were astonished to see the same brain circuitry light up that would activate if the monkey were eating the ice cream himself. Through this chance discovery it was shown that merely observing someone else performing an action brought about brain activity virtually identical to that observed if one were engaged in that activity himself.
Since then, scientific research has exposed a whole network of these mirror neurons in the brain. There are multiple mirror neuron systems, not just for mimicking actions, but for reading and feeling the emotions of others, for reading intentions, and for use in non-verbal social interaction. The sole job of mirror neurons is to feel and experience through others. To this date, mirror neuron systems have been found in several areas of the brain, including the premotor cortex, the posterior parietal lobe, the superior temporal salcus, and the insula. Not all that surprising, mirror neurons are more prominent in the human brain than in any other species. (Goleman, 2006)
Mirror neurons have an impact on everything we do. They are the brain's way of feeling what others feel, a sort of sixth sense. Within one hour of birth, mirror neurons are active in a baby's brain. If an adult sticks out his tongue, the newborn imitates the action. (Gopnik et al., 2000, p. 29) When we view an expression on another person’s face, our mirror neurons fire and we unconsciously tend to imitate those emotional expressions. (Dimberg & Thunberg, 2000; Dimberg et al., 2000) If shown a picture of a smile, people unconsciously and without even realizing it tend to smile. If shown a sad face, their facial muscles contract into a frown.
The effect from mirror neurons is so strong it can even play a role in lab research. When mice are bred to be genetically identical (for experimental control), the fact that their mirror neurons read the environment can skew the results of a study. Even when genetically identical, the mice will react differently depending on whether or not their researchers were 'sad' or 'happy.' (Crabbe et al., 1999) Scientists must take care to ensure a steady emotional control in their lab environments, because mirror neurons are hard at work reading the environment and will actually change the brain chemistry and alter the behavior of the animals being studied. This brings us to the more important aspect of mirror neurons, which is the extent to which they play a role in normal functioning. To understand this role, let's take a quick look at how the brain functions as a whole in everyday life.