RIKEN discovers that social metacognition and cognition are processed in different areas of the brain

Anterior lateral prefrontal cortex (alPFC47) plays an important role in social metacognition, in which one projects metacognition, an ability to recognize one's thoughts as if others were looking at them, onto others to predict the thoughts of others. This discovery was made by an international joint research group led by Team Leader Kentaro Miyamoto of the Laboratory for Imagination and Executive Functions at the RIKEN Center for Brain Science, using various tools, including new cognitive tasks and functional magnetic resonance imaging (fMRI).

Miyamoto said, "In this study, we found that social metacognition and cognition (understanding others based on knowledge) are processed in different brain areas. The findings are expected to contribute to developing organizational and management theories, such as team building or educational and other methods." The study was published in Nature Communications.

In educational and developmental psychology, the ability of the "theory of mind" to put oneself in the other person's shoes has been advocated to be important to understand the existence of the other person's mind. The temporoparietal junction (TPJ) is considered to be involved in this ability. However, because the experiences and abilities of others differ from one's own, the TPJ's function of replacing one's perspective with others is not sufficient to accurately predict the probability of success and level of performance before others actually fulfill the role.

To understand the state of others, it is necessary not only to understand the existence of others' minds but also to predict the state of others' minds by fitting "metacognition," an introspective evaluation of one's own mental model, to the mental model of others. Until now, the brain mechanisms enabling this ability have been completely unknown.

For a given task, one can predict the performance of a beginner who is less skilled than oneself, but it is difficult to predict the performance of a highly skilled expert. For example, one who has just earned a PhD in physics can predict the level of difficulty of a physics problem that a graduate student who has just entered a graduate school can solve. However, it should be difficult to predict the level of difficulty of a problem that a physicist with a longer career than oneself can solve.

To test this hypothesis, the research group developed a social metacognitive matching task. In this task, participants (27 graduate students in their 20s or 30s) were presented with two problems: one with a reward to be given to oneself if one answered a question correctly, and the other with a reward to be given to oneself if one's partner (another person) answered a question correctly. The participants chose one from which they are likely to be given the reward. Each problem involved a random-dot motion direction judgment.

In the experiment, the difficulty level of the problems presented to oneself and the partner (beginner or expert) varied from trial to trial. Therefore, participants were required to determine which problem would have a higher chance of receiving a reward for each trial based on various factors, including the difference in skillfulness between themselves and their partners. They compared the results of a task in which one had to predict and compare the performance between a beginner and oneself and a task in which one had to predict and compare the performance between an expert and oneself before making a choice. The hypothesis was found to be correct because the participants selected the person to answer with a higher probability of being rewarded more appropriately in the former task than in the latter task. In the former task, social cognition and metacognition can be used, while in the latter task, only social cognition can be used. Thus, the performance difference in selecting the appropriate person to answer between the two tasks reflects "social metacognition," an ability to predict the cognitive state of others based on a projection of metacognition onto others.

Comparisons of neural activity in the whole brain measured using fMRI during task execution showed that alPFC47 was active only during the former task, in which prediction can be made based on metacognitive projection. It was found for the first time that alPFC47 plays an important role as the neural basis in social metacognition. Furthermore, noninvasive and temporary suppression of neural activity in alPFC47 using transcranial magnetic stimulation (TMS) reduced the ability to compare performance prediction between oneself and a beginner to the same level in comparison between oneself and an expert. In this case, the performance in the random-dot motion direction judgments themselves was not affected at all. These results underpin the notion that alPFC47 plays a specialized role in the social metacognitive ability to predict others' cognitive states based on self-metacognitive projection to others.

Meanwhile, based on the results of fMRI experiments, they found that the TPJ activity intensifies according to the difficulty level of the partner's problem. This suggests that the TPJ plays a role in predicting the performance of others according to an empirical way of thinking.

This study revealed that alPFC47 is responsible for social metacognition, which is the ability to predict the state of mind of others based on projecting one's metacognition onto others, while the TPJ is responsible for social cognition, which is the ability to understand others based on knowledge and empirical rules. The findings are expected to contribute to the development of methods for educating and supporting people with developmental disabilities, such as autism spectrum disorder, from the perspective of developing training methods for understanding others through metacognitive projection.

Journal Information
Publication: Nature Communications
Title: Asymmetric projection of introspection reveals a behavioural and neural mechanism for interindividual social coordination
DOI: 10.1038/s41467-024-55202-0