What characterizes Japanese criminal psychology? An international comparison of research themes using semantic embeddings

This study positioned Japanese criminal psychology research within the international research space of criminal psychology and forensic psychology to examine cross-national differences in research priorities and knowledge structures. A total of 6,356 article abstracts published between 1963 and 2025 in the Japanese Journal of Criminal Psychology (JJCP) and five major international journals were analyzed. SPECTER2 embeddings were used to construct a semantic research space, followed by topic extraction, hierarchical clustering of higher-order research domains, and visualization using a self-organizing map. Differences between JJCP and international journals were examined using machine learning and Bayesian logistic regression. The analysis identified 47 research topics grouped into eight higher-order research domains. JJCP occupied a distinctive position within the international research space while maintaining connections with broader international research trends. Juvenile Delinquency and Correctional Classification was the topic most strongly associated with JJCP. Additional topics characteristic of JJCP included offender understanding, sexual offending, and correctional treatment, whereas international journals were characterized by juror judgment, evidence evaluation, and verdicts. These findings provide the first quantitative evidence that Japanese criminal psychology has developed a distinctive research profile within the international community. They also suggest that criminal psychology research priorities may reflect differences in institutional systems, professional traditions, and practical needs, highlighting the value of cross-national comparison for international knowledge exchange and the development of the field.