Emotions that are a mixture of positive and negative emotions are called mixed emotions. Culture influences what kinds of mixed emotions exist, sometimes regarded as emotions that symbolize a specific culture (e.g., saudade). However, there are few studies on mixed emotions in Japan, and it is unclear what kind of mixed emotions are likely to be experienced by Japanese people. The present study aimed to examine what mixed emotions are evaluated as typical among Japanese people, based on three studies. In a preliminary survey, 24 mixed emotion words were selected as candidates. In Study 1, mixed emotion words were evaluated regarding comprehension and emotional valence, and 12 were selected as more typical mixed emotion words. Finally, in Study 2, the 12 mixed emotion words were examined in more detail, and it was shown that "nagorioshii" and "aizou" in particular, may be typical mixed emotion words in Japanese people.

Belief in a just world entails the inclination to perceive the world as inherently fair and secure, where individuals are shielded from misfortune. While previous studies have focused on adults, none have comprehensively explored the developmental origins of just world beliefs. This study examined the development of two facets of just world beliefs - beliefs in immanent justice and ultimate justice- among participants aged five to nine and adults. Participants were presented with narratives depicting instances of either good or bad luck, followed by inquiries regarding the character's actions the previous day and predictions for the following day. The results exhibited a developmental difference in belief in immanent justice, evidence for the fortunate character during the initial half of age five and for the unfortunate character during the latter half of age seven. Conversely, belief in ultimate justice exhibited no developmental difference, indicating that it was already evident among five-year-olds. These findings suggest that belief in a just world takes root as early as the preschool years, although opportunities for further development persist.

The autonomic-based Concealed Information Test (CIT) relies on differential physiological responses to a specific item. We examined the impact of categorization rules on physiological responses in the CIT. The stimuli were numbers presented in various colors and participants randomly selected one to memorize. The CIT items comprised a number-congruent item, color-congruent item, and incongruent items; none were the same as the memorized item. In Experiment 1, these items were presented under different categorization rules. In the "unworkable" condition, participants were asked about the stimulus they had memorized, whereas in the "workable" condition, they were asked the color of the memorized stimulus. Notably, the number-congruent item in the "unworkable" condition elicited differential responses in electrodermal activity. In the "workable" condition, the color-congruent item prompted differential responses across all electrodermal, cardiovascular, and respiratory measures. No measure indicated a differential response to the number-congruent item. The findings from Experiment 1 were replicated in Experiment 2, where combinations of color and number varied across each repetition under the "workable" condition. This consistent pattern suggests the differential responses in the CIT is rule-based.

In the present study, a Japanese version of the Short Boredom Proneness Scale (SBPS) was developed, and its reliability and validity were examined. In addition, the effects of boredom proneness on eating behaviors, such as emotional eating and intuitive eating, were examined. In study 1,208 men and women completed the questionnaire. Confirmatory factor analysis revealed that the Japanese version of the SBPS had a one-factor structure similar to the original version, and the reliability and validity of the Japanese version of the SBPS were demonstrated. In study 2,782 men and women completed the questionnaire. A hierarchical multiple regression analysis indicated that the more easily bored one was, the more likely one was to engage in emotional eating. Regarding the moderating effect of emotion regulation strategies, the function of emotion regulation differed depending on sex and the characteristic factors of boredom. The results of this study suggest that by accounting for the characteristic factors of boredom, effective interventions for eating behavior may be enabled by accounting for the characteristic factors of boredom.

Using a foreign language is known to temporarily reduce the ability to think, due to the cognitive resources lost to language processing. This is called the foreign language side effect. Previous studies have shown that similarity of the structure in the foreign language used to that of the native language is associated with a smaller foreign language side effect. However, what defines a similar structure has not been clarified. This study examined whether the occurrence of foreign language side effects is due to syntactic analysis or lexical retrieval. Using a dual-task method to compare the degree of foreign language side effects between Japanese and English use among Chinese students demonstrated that the influence of lexical retrieval was larger than that of syntactic analysis.

This study aims to reveal the characteristics of auditory hypersensitivity among Japanese university students with a particular focus on two elements of auditory hypersensitivity: hyperacusis and misophonia. We conducted an investigation of the prevalence and interrelationship of these conditions in a non-clinical sample of 439 individuals using self-reported measures. Additionally, we performed a meta-analysis to compare our findings on hyperacusis and misophonia with the existing literature. Our results revealed a prevalence of 8.2% for hyperacusis, 40% for misophonia, and a 7.2% comorbidity rate for both conditions. Our meta-analysis indicated that our hyperacusis and misophonia scores are consistent with those reported in previous studies, but also suggested variability in these conditions across different countries. This implies that cultural and gender-related factors might influence the prevalence rates of hyperacusis and misophonia in the general population.