Shintaro Yukawa’s research while affiliated with Hakuoh University and other places

Previous research has shown that mind wandering has both positive and negative effects. Mind wandering may improve creative problem solving; however, it could also lead to negative moods and poor mental health. It has also been shown that some forms of mental illness are positively related to creativity. However, the three factors of mind wandering, divergent thinking, and mental health have not been examined simultaneously, so it is possible that these relationships are manifested by spurious correlations. Therefore, we examined the relations among the three factors while controlling for each of their confounding effects. We asked 865 participants (458 men, 390 women, 17 unknown; Mage = 18.99 years, SD = 1.16) to complete a questionnaire measuring mind wandering traits, divergent thinking, and mental health measures including depressive symptoms and schizotypal personality. Multiple regression analysis showed that people who reported more depressive symptoms, schizotypal personality, and divergent thinking, were more likely to engage in mind-wandering. Our results indicated that frequency of mind wandering was linked to a risk of poorer mental health as well as to higher divergent thinking ability. In future research, we will examine the features of mind wandering related to divergent thinking and mental health by considering the contents of wandering thoughts and whether they are ruminative or not. We also need to examine whether the same results will be found when studying professionals in creative occupations, and when using different scoring methods in divergent thinking tests.

The purpose of this study was twofold: (a) to examine the actual circumstances of involvement in gambling, and (b) to investigate the relationships between levels of the gambling problem and the Big Five personality traits among Japanese adults. Nine hundred Japanese adults were asked to complete a web-based questionnaire to measure their levels of involvement in gambling and personality traits. The results indicated that approximately 47% of the participants had engaged in gambling before. In addition, a positive relationship was observed between levels of gambling involvement and Neuroticism, while Agreeableness and Conscientiousness were negatively related to levels of gambling involvement.

Enhancing creative problem-solving is increasingly important in a modern globalized society. Previous research has shown that creative problem-solving can be improved if the mind is allowed to wander during time set aside from solving a problem, known as the incubation period. However, some research also suggests that mind wandering leads to negative affect. Our study aims to clarify the effect of mind wandering during the incubation stage on both creative problem-solving and mood while controlling for the effect of working memory capacity. Fifty-two students (both undergraduate and graduates) completed a working memory task and repeated a creative problem-solving task at intervals before and after an incubation period. At the end of the incubation period, we measured participants’ frequency of mind wandering and their moods. Results showed that the group with the higher frequency of mind wandering showed the most improvement in one indicator of creativity, flexibility, although this finding was not significant after adjusting for the other four facets. Moreover, our findings indicate that as creativity improved, more negative affect was generated. Our results suggest that mind wandering during the incubation stage could be used to generate more diverse ideas but also suggest that there is a risk attached. Further research should explore how specific features of mind wandering might improve creativity without generating negative affect.

Many studies have been done recently on the topic of mind wandering. The importance of distinguishing between intentional mind wandering and unintentional mind wandering has been emphasized. In the present study, Japanese versions of the Mind Wandering: Deliberate (MW-D) and the Mind Wandering: Spontaneous (MW-S) scales (Carriere et al., 2013) were developed, and the reliability and validity of the scales were examined. Undergraduates (N=357) completed the questionnaire. Analysis of the scores confirmed a 2-factor structure similar to the original English version. Moreover, the reliability and validity of the scales were confirmed using both questionnaire and experimental data from 60 participants. The present study demonstrated that the Japanese versions of the Mind Wandering: Deliberate and the Mind Wandering: Spontaneous scales had acceptable reliability and validity.

Promoting creativity is considered useful for society. Although some people believe that creative people generally have poor mental health, recent published studies have suggested that some highly creative people are mentally very healthy. Therefore, the present study focused on a phenomenon called "mind wandering," a concept that is associated with both creativity and mental health, and examined whether characteristics of mind wandering differed, depending on an individual's level of creativity and mental health. After the participants (N=62: 40 men, 22 women; average age 19.67 years) had completed questionnaires measuring their creativity, level of depression, and working memory capacity, they watched a video. While they were watching it, the thought content of their mind wandering, their level of awareness, and the number of topics included when mind wandering were measured, using the thought probe method. The results suggested that the participants who had scored high on creativity and low on depression, that is, whose scores indicated high mental health, did not think excessively about past events during episodes of mind wandering. These results suggest that mind wandering may be a fundamental way to improve creativity while maintaining mental health.

Stressful experiences can lead to meaning making that is seen as central in adjustment. Although rumination and negative affect are important factors of meaning making, little is known about the mechanisms involved. This study aimed to examine the meaning making process, focusing on the role of intrusive and deliberate rumination and negative affect. The principal hypotheses were as follows: negative affect is positively related to threat evaluation and intrusive rumination, while regret and guilt are positively related to deliberate rumination; intrusive rumination is negatively related to finding meaning, whereas deliberate rumination is positively related to finding meaning. A total of 383 undergraduate students were asked to remember their most stressful life event and complete a questionnaire containing the Event Related Rumination Inventory and items about negative affect, threat evaluation, and finding meaning about the stressful life event. For 342 of the final sample, structural equation modeling based on the study hypotheses showed that both deliberate and intrusive rumination immediately after the event were positively associated with finding meaning. Intrusive rumination at present, however, was negatively related to finding meaning. This study also revealed the effects of negative affect: helplessness, sadness, and fear induced intrusive rumination; moreover, regret was positively associated with deliberate rumination.