Given graphs \(X\) and \(Y\) with vertex sets \(V(X)\) \(V(Y)\) of the same cardinality, we define a graph \(\mathsf{FS}(X,Y)\) whose set consists all bijections \(\sigma\colon V(X)\to V(Y)\), where two \(\sigma\) \(\sigma'\) are adjacent if they agree everywhere except for vertices \(a,b \in V(X)\) such that \(\sigma(a)\) \(\sigma(b)\) in \(Y\). This setup, which has natural interpretation ter...

Unlike other primates, humans exhibit extensive inter-group tolerance and frequently build relationships with out-group members. Despite its common occurrence, little is known about the conditions leading to out-group relationship building in humans. What are the social and ecological factors promoting valuation of out-group members as potential social partners? Do they differ from those promot...

The purpose of this study was to examine the relationship between homeless youths' HIV risk behaviors with strangers and risk and protective characteristics of their social networks. Data were from the Social Network and Homeless Youth Project. A total of 249 youth aged 14-21 years were interviewed over 15 months in three Midwestern cities in the United States using a systematic sampling strate...

The uncanny valley hypothesis predicts that an entity appearing almost human risks eliciting cold, eerie feelings in viewers. Categorization-based stranger avoidance theory identifies the cause of this feeling as categorizing the entity into a novel category. This explanation is doubtful because stranger is not a novel category in adults; infants do not avoid strangers while the category strang...

BACKGROUND Discriminating threatening individuals from non-threatening ones allow territory owners to modulate their territorial responses according to the threat posed by each intruder. This ability reduces costs associated with territorial defence. Reduced aggression towards familiar adjacent neighbours, termed the dear-enemy effect, has been shown in numerous species. An important question t...