Friendly smiles for difficult times

A lot of signaling goes on within the context of social situations. Humans are the most social of animals. The importance of not only sending the correct social signals, but reading them correctly as well is of paramount importance. Further, the greater the stakes, the more important the signaling is.

The following paper is on ‘smiling’ as a social signal; but its conclusions could be broadened to other forms of social signaling. The ability to gain allies and cooperation within a group is of extreme importance in challenging environments.

Smiling is a Costly Signal of Cooperation Opportunities: Experimental Evidence from a Trust Game (pdf)
Samuele Centorrino, Elodie Djemai, Astrid Hopfensitz, Manfred Milinski, Paul Seabright, 11 April 2011. Ht MR.

We test the hypothesis that "genuine" or "convincing" smiling is a costly signal that has evolved to induce cooperation in situations requiring mutual trust. Potential trustees in a trust game made video clips for viewing by potential trusters before the latter decided whether to send them money. Ratings of the genuineness of smiles vary across clips; it is difficult to make convincing smiles to order. We argue that smiling convincingly is costly, because smiles from trustees playing for higher stakes are rated as significantly more convincing, so that rewards appear to induce effort. We show that it induces cooperation: [convincing] smiles strongly predict judgments about the trustworthiness of trustees, and willingness to send them money.

It is an honest signal: those smiling convincingly return more money on average to senders. Convincing smiles are to some extent a signal of the intrinsic character of trustees: less honest individuals find smiling convincingly more difficult. They are also informative about the greater amounts that trustees playing for higher stakes have available to share: it is harder to smile convincingly if you have less to offer.

I also like the quote that starts their work:

The man who indulges us in this natural passion, who invites us into his heart, who, as it were, sets open the gates of his breast to us, seems to exercise a species of hospitality more delightful than any other. No man, who is in ordinary good temper, can fail of pleasing, if he has the courage to utter his real sentiments as he feels them, and because he feels them. Adam Smith – The Theory of Moral Sentiment.