Shame can be a social event (e.g., being judged and shamed in the eyes of others) or a private feeling linked to our judgments of our feelings, ability to fantasize, and characteristics. Shame can guide behavior, influence feelings about ourselves, and shape our sense of self-identity and feelings about our social acceptability and desirability [1–3].
Correlations have been found between shame and many psychiatric symptoms, such as borderline personality disorders , eating disorders [5, 6], anxiety , depression [3, 8, 9], and paranoia , among others. Therefore, shame is an essential factor related to mental health.
According to Gilbert , two types of shame exist. One is “internal shame,” which is related to the internal dynamics of the self and how the self judges and feels about itself . Internal shame relates to the tendency to attend to negative aspects of the self and to maintain global self-judgments of the self as bad, inferior, and flawed [1–3]. The other type is “external shame,” which is associated with the following tendencies: being worried that others would see the self as uninteresting or boring and, thus, the self would be rejected or excluded from valuable relationships . External shame has been defined as shame that arises primarily from the process of being shamed by others, which is the source of this type of shame [1, 11].
External shame is caused by the consciousness of others, that is, the concept that the self is negatively evaluated by others, which is correlated with depression , one’s body image related to eating disorders , and one’s self-image related to social anxiety disorders . However, in Japan, no standardized scales exist to measure external shame.
Moreover, the suggestion has been made that most stress response scales in Japan were developed based on classical test theory . Classical test theory has a significant problem that survey results are highly affected by the characteristics and quality of the sample because statistics are defined based on the population . Item response theory (IRT) is a paradigm for solving this problem. Different from the reliability coefficient that previously assessed the mean accuracy of an entire scale, IRT measurement accuracy is expressed as a function of characteristic values on a continuous scale that indicates latent traits (θ) and a point at which a measurement value with high accuracy is indicated about the entire test as well as being based on each item. Therefore, the appropriateness of each item can be judged from the perspective of the measurement purpose of the test . Moreover, the practical utility of the scale can be examined from diverse perspectives.
Based on this information, this study aims to explore the development of the Japanese version of the OAS to assess trait shame—especially external shame. The reliability and validity of the OAS were also examined, and its measurement accuracy was examined using the IRT.