"Brothers" in Arms: Does Metaphorizing Kinship Increase Approval of Parochial Altruism?

Abstract

Parochial altruism is manifested in the most violent of conflicts. Although it makes evolutionary sense for kin, many non-kin groups also behave parochially altruistically in response to threat from out-groups. It is possible that such non-kin groups share a sense of "fictive" kinship which encourages them to behave parochially altruistically for each other's benefit. Our findings show that individuals not directly involved in a conflict approved of parochial altruism enacted by an in-group against an out-group more when the out-group posed a threat to the in-group; however, this effect was greater when the in-group members expressed fictive kinship by addressing each other using kinship met..