Abstract
The evolutionary theory of loneliness (ETL) posits that loneliness poses significant risks to morbidity and mortality. When individuals are lonely, both their physical and psychological safety may rely, in part, on the ability of conspecifics to detect their loneliness so they can offer protective and corrective actions. Building on ETL, we propose that loneliness is detectable at greater-than-chance levels via communicative behaviors, signaling that individuals are struggling to meet their needs for connection. In the present experiment, 853 observers evaluated self-presentation messages from high- and low-loneliness speakers. We hypothesized that observers can detect speakers' loneliness at greater-than-chance levels and that nonverbal safety behaviors and verbal relational references mediate the association between a speaker's loneliness and the detection of that loneliness. Speakers' speaking rate, use of relational terms and use of personal pronouns significantly mediated the association between the speakers' loneliness and observers' perceptions of the speakers' loneliness. These findings demonstrate ETL's claim that lonely individuals signal their loneliness socially, perhaps as a means of eliciting support.