Page "Altruism" Paragraph 19

* Kin selection.

That animals and humans are more altruistic towards close kin than to distant kin and non-kin has been confirmed in numerous studies across many different cultures.

Even subtle cues indicating kinship may unconsciously increase altruistic behavior.

One kinship cue is facial resemblance.

One study found that slightly altering photographs so that they more closely resembled the faces of study participants increased the trust the participants expressed regarding depicted persons.

Another cue is having the same family name, especially if rare, and this has been found to increase helping behavior.

Another study found more cooperative behavior the greater the number the perceived kin in a group.

Using kinship terms in political speeches increased audience agreement with the speaker in one study.

This effect was especially strong for firstborns, who are typically close to their families.