齋藤 慈子

Abstract Although oxytocin (OT) plays a role in bonding between heterospecifics and conspecifics, the effects of OT on the formation of such interspecific social behavior have only been investigated between humans and dogs (Canis familiaris). In this study, for comparative evaluation of the effects of OT between dog–human and cat–human social interaction, we investigated the effects of exogenous OT on the behavior of domestic cats (Felis silvestris catus) toward humans. We intranasally administered OT or saline to 30 cats using a nebulizer and recorded their behavior (gaze, touch, vocalization, and proximity). The results showed an interaction between the administration condition and sex for gaze duration. Post hoc analyses revealed a significant increase in gaze in the OT condition in male cats but not in females. There were no significant differences in gaze toward owners and strangers in any condition or sex. The male-specific OT-mediated increase in gaze toward humans observed in this study differs from previous research on dogs wherein such effects were observed only in females. These findings suggest an overall effect of exogenous OT on cats’ social relationship with humans as well as the possibility of different mechanisms between cat–human and dog–human relationships.

The size and regulation of personal space are reportedly atypical in autistic individuals. As personal space regulates social interaction, its developmental change is essential for understanding the nature of social difficulties that autistic individuals face. Adolescence is an important developmental period in which social relationships become complex. We conducted a three-year longitudinal study of interpersonal distances in autistic and typically developing (TD) individuals aged 12-18 years at Time 1 and 15-21 years at Time 2. Their preferred interpersonal distances were measured when an experimenter approached the participants with and without eye contact. The interpersonal distances of autistic individuals were shorter than those of TD individuals at both Time 1 and Time 2. Furthermore, the interpersonal distances of autistic individuals at Time 1 and Time 2 were highly correlated, but no such correlation was found in TD individuals. The results suggest that the interpersonal distances of autistic individuals are stable and that the shorter preferred interpersonal distances in autistic individuals compared to those of TD individuals are maintained during adolescence.

Children's secure attachment with their primary caregivers is crucial for physical, cognitive, and emotional maturation. Yet, the causal links between specific parenting behaviors and infant attachment patterns are not fully understood. Here we report infant attachment in New World monkeys common marmosets, characterized by shared infant care among parents and older siblings and complex vocal communications. By integrating natural variations in parenting styles and subsecond-scale microanalyses of dyadic vocal and physical interactions, we demonstrate that marmoset infants signal their needs through context-dependent call use and selective approaches toward familiar caregivers. The infant attachment behaviors are tuned to each caregiver's parenting style; infants use negative calls when carried by rejecting caregivers and selectively avoid neglectful and rejecting caregivers. Family-deprived infants fail to develop such adaptive uses of attachment behaviors. With these similarities with humans, marmosets offer a promising model for investigating the biological mechanisms of attachment security.