Reading frequency and Kawaii-Related Oshikatsu: Positive correlations with gray matter volume in Indoor lifestyles.

Reading and kawaii-related oshikatsu (fan support activities) are among the most widely enjoyed hobbies. Previous studies have shown that gray matter volume (GMV) of the insular cortex is associated with the degree of alexithymia, which is linked to reduced mentalizing ability and motivation, and that inter- and intra-insular networks are related to reading. Similarly, studies suggest that by stimulating motivations for protection and caregiving, the insula-associated with empathy and reward processing-plays a role in responses to infants and other kawaii objects (i.e., objects perceived as cute). Building on this evidence, it is meaningful to investigate the neural basis of reading and kawaii-related oshikatsu within the insular cortex and to clarify its relationship with brain structure from a cognitive neuroscience perspective. Therefore, the present study tested the relationship using a sample of 82 healthy adults (52 men, 30 women) aged 22 to 65 years, controlling for demographic variables. A hierarchical multiple regression analysis using insular GMV as the dependent variable revealed significant positive associations with both reading frequency and kawaii-related oshikatsu. The finding suggests that these activities are not merely cognitive functions but are closely linked to social-cognitive processes essential for human survival, such as emotional processing, mentalizing, and nurturing behavior.