A new cross-temporal meta-analysis suggests that Japanese people have become measurably less extraverted over the past decade, providing empirical support for a long-running public conversation about Japan becoming more “inward-looking.” The study, conducted by Ryonosuke Akimoto, now a master’s student at The University of Tokyo, and Yuji Ogihara, an associate professor at Aoyama Gakuin University, examined personality data collected from Japanese participants between 2010 and 2021. Its findings point to a sustained decline in extraversion among both men and women, a pattern that appears to differ sharply from personality trends reported in several other countries.
Extraversion is one of the five broad dimensions commonly used to describe human personality. It is associated with sociability, activity, assertiveness, enthusiasm and the tendency to seek stimulation through interaction with other people. Lower extraversion does not necessarily mean that an individual is isolated or unhappy, but it generally reflects reduced social energy or a weaker inclination toward highly active and outgoing behavior. In Japan, commentators have for years described younger generations as increasingly reluctant to study or work abroad, and public discussions have often presented this as evidence of a national shift toward inward-looking attitudes. Until now, however, those claims had not been tested comprehensively using population-level psychological data.
To investigate the issue, the researchers systematically gathered previous studies that had measured extraversion among Japanese participants. Their analysis focused on the Japanese version of the Ten Item Personality Inventory, known as the TIPI-J, a concise personality questionnaire introduced in Japan by Oshio and colleagues. The scale measures the Big Five traits using ten items, with participants rating how accurately paired descriptions represent them. Although brief measures can contain more measurement error than lengthy personality inventories, the TIPI-J was the most frequently used extraversion scale in recent Japanese research, allowing the investigators to compare results across multiple samples and years.
The researchers collected studies published from 2012 through 2022, while examining data covering the period from 2010 to 2021. They used statistical methods designed to identify changes in average extraversion scores over time while adjusting for participant characteristics that might otherwise distort the results. Age and gender were among the controlled variables, because personality scores can differ systematically across demographic groups. This approach, known as a cross-temporal meta-analysis, does not follow the same individuals throughout their lives. Instead, it evaluates whether the average scores reported by comparable samples change across historical time, making it possible to detect broad population-level shifts.
The results showed a consistent downward trend in Japanese extraversion. The decline was observed in analyses of men and women, and the magnitude of change was broadly similar between the two groups. The pattern also remained when the researchers examined students separately and when they analyzed adults between 20 and 60 years old. Because insufficient data were available for a reliable analysis of older adults, the elderly group was excluded from those age-specific comparisons. Even with that limitation, the repetition of the trend across different samples strengthened the researchers’ conclusion that the result was not simply caused by one unusually large study or by a narrow demographic group.
The timing of the data raised an important question: could the apparent decline be primarily an effect of the COVID-19 pandemic? Previous research has shown that infectious-disease outbreaks can reduce social activity and influence personality-related behavior, including extraversion. To address this possibility, Akimoto and Ogihara repeated their analysis using only data collected through 2019, before the pandemic began. This restricted analysis also indicated a decline in extraversion between 2010 and 2019. The finding suggests that COVID-19 may have intensified social withdrawal in Japan, but it cannot fully explain the longer-term pattern identified in the study.
The Japanese trajectory contrasts with findings reported from several other countries. Earlier research has described increases in average extraversion in the United States, China, the Netherlands and Sweden. Those studies used different datasets, instruments and historical periods, so direct international comparisons must be interpreted cautiously. Nevertheless, the opposing direction of the trends is striking. If the patterns are confirmed using harmonized measures and broader samples, Japan may represent an unusual case of national-level personality change. The contrast could help researchers investigate how economic conditions, education systems, technology use, social expectations, demographic change and cultural norms influence personality across generations.
The study does not establish why extraversion has declined, nor does it show that Japanese people have biologically become less sociable. Cross-temporal research can identify associations between historical period and average personality scores, but it cannot by itself determine which social forces produced them. Changes in the composition of study samples, differences in survey settings, shifting interpretations of questionnaire items or changes in response styles could contribute to the observed pattern. The authors therefore describe their findings as evidence of a population trend rather than proof of a single cause. Longer-term studies, nationally representative sampling and consistent measurement across decades will be needed to determine whether the decline continues and how large it is in the wider population.
The researchers also emphasize that a reduction in average extraversion should not automatically be interpreted as a social crisis. Personality traits exist on continua, and lower extraversion can be accompanied by qualities such as reflection, independence or preference for smaller social environments. However, a broad shift could still have consequences for education, workplaces, international mobility, interpersonal relationships and public policy. The findings offer a data-based perspective on a cultural concern that has often been discussed through anecdotes and media commentary. By documenting a measurable change before and during the pandemic era, the study opens a new line of research into how Japanese society is changing psychologically—and whether alterations in extraversion are linked to parallel shifts in other personality traits and social indicators.
The article, titled “Decline of Extraversion in Japan: A Cross-Temporal Meta-Analysis,” was published open access in Personality Science on June 26, 2026. The authors plan to examine the possible causes of the decline and to study its relationship with broader cultural and socioeconomic changes. For now, the central message is clear: the idea that Japanese people are becoming more inward-looking is no longer supported only by public impression. Across a collection of previous studies and multiple demographic analyses, the data reveal a distinctive decline in extraversion from 2010 to 2021—one that may place Japan on a personality trajectory unlike those reported elsewhere.
Subject of Research: Not applicable
Article Title: Decline of Extraversion in Japan: A Cross-Temporal Meta-Analysis
News Publication Date: Not specified in the provided content
Web References: https://doi.org/10.1177/27000710261452522
References: Oshio et al. (2012); Twenge (2001); Peng & Luo (2021); Smits et al. (2011); Billstedt et al. (2013); Mortensen et al. (2010); Burgess (2015); Kikuchi et al. (2015); Yonezawa (2014)
Image Credits: Ryonosuke Akimoto, Yuji Ogihara
Keywords: Japan, extraversion, personality change, Big Five personality traits, cross-temporal meta-analysis, TIPI-J, introversion, cultural change, COVID-19, psychology
