Psychologists and philosophers have long suggested that simulation is the mechanism whereby humans understand the minds of others. However, the neural basis of this complex process had not been identified until a group of researchers identified a type of neuron that had not previously been described that actively and spontaneously learns from decision-making by other individuals and simulates their mental processes.
It was not known whether specific neurons contributed to advanced social knowledge, such as simulating the decisions of other individuals. The dysfunction of these simulation neurons might be involved in the restriction of social knowledge, one of the symptoms of autism and, through hyperactivity, may give an exaggerated version of others and play an important role in social anxiety, the authors speculate.
The study, published in Cell, one of the journals with the highest impact factor, is the result of research led by Wolfram Schultz, a scientist at the University of Cambridge (UK) involving Gustavo Deco, ICREA research professor with the Department of Information and Communication Technologies (DTIC) and director of the Center for Brain and Cognition (CBC) at UPF.
Anything that is captured in the subconscious will directly affect us in the form of emotions, circumstances and events. There is more and more research investigatng what thoughts and ideas govern our mind.
The work suggests that these so-called “simulation neurons”, found in the amygdala, a collection of nerve cells in the brain’s temporal lobe, allow animals (and potentially also humans) to reconstruct the mental state of their social partners and, therefore, predict their intentions.
The simulation of decisions is involved in social learning
The first author of the study, Fabian Grabenhorst, a researcher at the Department of Physiology, Development and Neuroscience at the University of Cambridge explains: “We started to look for neurons that might be involved in social learning. We were surprised to discover that neurons in the amygdala not only learn the value of the objects of social observation, but they used this information to simulate the decisions of their partner”.
The simulation of the decisions of others is a sophisticated cognitive process within social learning. “For example, by observing the foraging choices of another individual, we can learn what food is worth choosing. This knowledge is not only to do with our own decisions, but also help us to predict the future decisions of others”, says Gustavo Deco, co-author of the study.
For the study, the researchers recorded the activity of amygdala neurons in monkeys while participating in observational learning tasks. Positioned in pairs, facing each other, with a touch screen between them, the animals had to take a decision if they wanted to receive the reward (fruit juice). To maximize their reward, the animals had to learn and monitor the likelihood of reward associated with the different images displayed to them on the screen. The study allowed the animals to observe the choices taken by their partner and learn the reward values of each image. The researchers saw that once the images were switched, the observing animal could make use of this knowledge when it was the recorded monkey’s turn to choose.
Surprisingly, it was seen that when an animal observed its partner, the neurons in the amygdala of the observer seemed to make a decision computation. These neurons were able to make a prediction about the reward value of the partner’s choices before taking a decision, which is in line with a simulated decision-making process. It is important to highlight that these patterns of activity occurred spontaneously, long before the partner’s choices and options without the need for a decision by the observer.