Fiscal Year
FY 2025
April 2025 – March 2026

Principal Investigator
Yumi Hamamoto
Assistant Professor, Division for the Establishment of Frontier Sciences, Frontier Research Institute for Interdisciplinary Sciences / Research Institute of Electrical Communication

Co-Investigators
Erina Miyatsu
Department of Human Brain Science, Graduate School of Medicine

Research Keywords
Rejection sensitivity ; Perfectionism ; fMRI

1. Research Overview

Perfectionism is known to be associated with a variety of mental health problems, including depression, social anxiety, and eating disorders. Previous research has suggested that one reason for this is rejection sensitivity—a tendency to anticipate, perceive, and overreact to rejection by others—which makes perfectionists prone to feelings of loneliness in their relationships. Clarifying the interpersonal situations in which rejection sensitivity arises in perfectionists is therefore important for understanding the related mental health problems.

One previous study suggested that, because perfectionists respond distinctively to mistakes, rejection sensitivity arises when they make mistakes in front of others. On the other hand, it has also been pointed out that rejection sensitivity may arise in response to the mere presence of others, even before any mistake occurs. Which of these situations triggers rejection sensitivity has remained unclear. In this study, we examined this question using a neuroscientific method, functional magnetic resonance imaging (fMRI).

Specifically, we focused on several brain regions previously reported to be associated with social rejection and tested whether their activity was related to perfectionism scores in two situations: when others were present, and when participants made mistakes in front of others. The analyses revealed positive correlations with perfectionism scores in some of the rejection-related brain regions in both situations, with different regions involved in each. These results suggest that the more perfectionistic a person is, the stronger their rejection-related neural responses are—both when others are merely present and when they make mistakes in front of others—indicating that rejection sensitivity in perfectionism may arise in both situations.

This study is one of the first to reveal the neural basis of perfectionism while taking social context into account, showing that individuals with high perfectionism may exhibit heightened rejection-related neural responses even when they are not actually being rejected. Moreover, by examining “making mistakes in front of others” and “the presence of others” as independent conditions, the study showed that rejection sensitivity in perfectionism may not be a single process but may consist of at least two cognitive processes: anticipation of and concern about rejection triggered by the mere presence of others, and an attempt to infer “how the other person sees me” after making a mistake in front of them. These findings shed light on the mechanism underlying rejection sensitivity in perfectionism at the neural level and contribute to understanding perfectionism-related mental health problems.

2. Significance of the Research and Future Prospects

The results of this study contribute to elucidating the mechanism of rejection sensitivity, which links perfectionism to mental health problems. Today, with the spread of social media and AI, situations that demand “being perfect” are increasing, and the number of people with perfectionistic tendencies is growing. Amid concerns that perfectionism-related mental health problems will increase accordingly, this study is expected to contribute to the understanding and treatment of such problems by revealing the neural basis of rejection sensitivity in interpersonal situations among highly perfectionistic individuals.

The study also has both academic and clinical significance. Academically, its novelty lies in being the first to distinguish in which interpersonal situations, and through which neural bases, rejection sensitivity in perfectionism arises—a phenomenon that had previously been discussed as a single construct. Clinically, the findings suggest that in highly perfectionistic individuals, neural activity related to sensitivity to others’ evaluations and anticipation of rejection may already be elevated before any actual rejection occurs. This highlights the importance of attending not only to experiences of rejection themselves but also to the preceding cognitive processes when supporting people with perfectionism-related mental health problems.

Furthermore, by combining psychological questionnaires with brain imaging (fMRI), this study is an interdisciplinary attempt to understand the psychological trait of perfectionism at the level of the brain. This approach is consistent with the philosophy of the So-Go-Chi project, which aims for a comprehensive understanding of the human mind and brain. Future work will examine whether the cognitive processes identified in this study—anticipation of rejection and heightened sensitivity to others’ evaluations—are effective targets for intervention, with the aim of applying these findings to the prevention and treatment of perfectionism-related mental health problems.

3. Conclusion

This study used a neuroscientific method (fMRI) to examine the interpersonal situations in which highly perfectionistic individuals feel excessively rejected by others. The results showed that, both when others are merely present and when a mistake is made in front of others, stronger perfectionistic tendencies are associated with greater activity in brain regions related to social rejection. Furthermore, the involvement of different brain regions in each situation suggests that this “sensitivity to rejection” is not a single response but consists of at least two cognitive processes: anticipating rejection in advance, and trying to read the other person’s intentions after making a mistake. These findings are expected to contribute to elucidating the mechanism linking perfectionism and mental health problems.