Affiliative terms as a linguistic tool for improving perceptions of out-group members?

Group-contingent prosociality pervades human societies but the payoffs associated with inter-group tolerance and cooperation act as counterforces. Kinship terms (e.g. ‘brother’) and affiliative terms (e.g. ‘mate’) have been proposed to function to create strong bonds among in-group members but it is unknown if they play a role in establishing or strengthening between-group ties. To explore that possibility we conducted a psychological experiment whereby we recorded six speeches by three male speakers that differed along two lines: i) the accent of the speaker (Australian English, British English and English with a foreign accent), and ii) the inclusion of the word ‘mate’. Listeners (N=90; 45 males and 45 females) rated each vocal stimulus in terms of trustworthiness using a Likert scale. Our results support existing literature that subjects regard speakers with their own dialect as having higher trustworthiness. However, results do not accord with the notion that affiliative terms are harnessed to get access to social capital within and between groups. In sum, while accents can serve as reliable markers allowing selective assortment among individuals, affiliative terms do not seem to have such social utility (probably because they are easy to fake and thus do not constitute honest signals).