New research indicates that rats have more emotional intelligence than previously assumed. 

Humans normally show empathy for their fellow human beings. When we see someone crying, we often feel sad. When we see someone cut their finger or break a limb, we will wince. Researchers in the Netherlands have demonstrated that rats also respond to the pain experienced by other rats.

Neuroimaging studies in humans have shown that the cingulate cortex in the brain becomes activated when we experience pain and when we witness pain in others. However, the hypothesis, that there are ‘mirror neurons’ on the cingulate cortex that trigger both our own feeling of pain and the empathy when we witness pain in others has never been confirmed, as recording of such activity presents problems in humans.

However, the researchers have managed to confirm this phenomena in rats. When rats were made to look at a fellow rat receiving an unpleasant stimulus, the observing rats froze – a typical fearful response (to avoid being detected by a predator). At the same time they observed activity in the cingulate cortex of the observing rats. Furthermore, when the activity of the cingulate cortex was suppressed (through drugs), the observing rats did not exhibit empathy – they did not freeze when their fellow rats experienced pain and continued with their other activities.

The researchers commented that with rats and humans showing the same fundamental mechanisms of pain empathy, with activity in the same part of the brain, it suggests that the ability to feel the emotion of others is deeply rooted in our evolution.

It is hoped that this research will help in the understanding of various mental disorders, where lack of empathy is a symptom of a number of conditions. The fact that rats respond to the pain of others may explain the avoidance of traps in certain circumstances.

Further reading: Carrillo et al. (2019). Emotional Mirror Neurons in the Rat’s Anterior Cingulate Cortex. Current Biology, 2019; DOI: 10.1016/j. cub.2019.03.024