Communication with bodily expression gains empathy

Cognitive science is a discipline that studies how humans process various inputs such as visual and tactile senses to shape their thinking and actions. This involves a variety of disciplines from psychology and philosophy to linguistics, cultural anthropology, information science, computer science, and AI (Artificial Intelligence). Among them is also cognitive neuroscience, a discipline that tries to understand humans in terms of brain information processing.

Many people may think that research on the brain focuses on thinking and consciousness, but in my Cognitive Neuroscience Laboratory, the big keyword for research themes is actually “body.” Information coming into the brain originates from what the body senses, and after such information is processed by the brain, instructions to act on the environment will be given to the body. In that sense, the body is indispensable for brain activities; but what is more, the body is heavily involved in how the brain recognizes the environment and makes decisions. In the case of a computer, inputting the same information results in the same response. In the case of a human, however, responses (that is, decisions by the brain) to the same information vary depending on whether the person is, for example, in good or poor health. In addition, the way the environment is recognized differs between early childhood when the body size is small and young adulthood when it is large. Therefore, the body of a human is different from a simple input device in a computer and is considered to be deeply embedded in the function of the brain. Recognition in the brain is based on not only perceptual information but also the information of bodily movements, which are actions on the environment; thus, we can say recognition in the brain and bodily movements form a loop structure.

A further interesting thing about the relationship between the brain and body is that the brain has an area called the “mirror neuron system.” When you exercise, the motor area of your brain works. However, it also works when you are simply watching other people exercise even without actually engaging in the activity yourself. This suggests that the human brain engages in simulation simply by watching the motions of other people. It is thought that one of the reasons that this simulation might occur is because humans have a latent desire to understand one another, and as such, simulation occurs in order to speed up the facilitation of this process. Communications, a means to understand others, are generally considered to be verbal exchange of information. However, observation of the brain reveals that besides the exchange of verbal information at a high level, communication based on information processing of the body is also performed at a lower level. Such communication without words is called “non-verbal communication”, and some research even suggests that it is actually more important than verbal information. For example, seeing a friend feel sad about an unfortunate event can also makes us feel sad as well. This is a phenomenon called “empathy”, which is the identification of oneself with other people. This is also caused by the mirror neuron system. In this case, you are not trying to empathize consciously; instead, simulating the actions of other people automatically makes you feel a similar emotion. That is, empathy is generated when the boundaries between oneself and other people disappear due to resonance at the physical level, resulting in overlap with them in the brain. By dynamically switching between the states of overlapping with others and getting away from others, humans have enhanced their sociality.

In fact, non-human animals are also known to exhibit the effects of the mirror system in their brains well. A bird who imitates the chirping of a parent bird is an example of behavior due to the mirror system. However, humans do not just feel empathy from physical resonance based on the mirror system; we have also developed the ability to infer what other people’s feelings are (act of inference). This is called “mentalizing.” The phenomena of resonance and empathy take place automatically at the physical level, whereas with mentalizing, the mental state of other people is inferred consciously so that we can decide which actions we should take in response. Such a process is rarely found in other animals. Some experts say that humans have been able to construct complex societies in a way that other animals simply cannot because our brains have been developed for this mentalizing function. This idea is called the “social brain hypothesis.” For example, if we examine how primate brain size is related to the size of the group that they can form, we find a correlation between these two factors. Chimpanzees can form a group of dozens, but larger-brained humans can form groups of about 150 to 200 individuals, each of which can still belong to many different groups at other locations.