Good manners: signaling social preferences

There is evidence that people also care about social norms like fairness independently of the approval or disapproval they get by conforming to or violating them, but for parsimony our model will not attempt to capture this kind of social preference.

Benabou and Tirole (2006) recognize that self-image can matter as much as social image. The omission of self-image concerns from our model is solely for simplicity.

These behaviors might also feel wrong in that they create work for one’s colleagues, but while people generally are altruistic (and so they do take this into account), they are not generally so altruistic that they would rather do work themselves that their colleagues could just as well do.

Player i’s self-centered utility, as defined in Eq. (1), depends on other players’ types, but because the expectation is taken inside the function S, this utility is not equal to the expected posterior utility after discovering each other player’s type (unless S is linear). That is, we assume that people care about their beliefs about how much others like them (as they may never know for sure how others feel). Technically, we might consider this interaction a psychological game (Geanakoplos et al. 1989; Rabin 1993), but we do not require the machinery of psychological game theory. While psychological game theory allows players’ utilities to depend on a full hierarchy of beliefs about other players’ strategies, we assume that players’ utilities depend only on beliefs about a state of nature. We can still use Harsanyi’s (1967) method of positing a type space to model the interaction as a Bayesian game, only we use Eqs. (1) and (2) to define utility, rather than deriving an expected utility from utilities defined when known types interact.

Farrell (1993) and Grossman and Perry (1986) prescribe attributions of a single unexpected message whereas Matthews et al. (1991) prescribe attributions of a set of unexpected messages. In general, multiple attributions may be possible. Farrell (1993) requires consistency with all possible reasonable attributions, whereas Grossman and Perry (1986) require consistency with some reasonable attribution.

This definition of cheap talk does not assume that it is not credible and allows it to affect utilities if it is believed.

Our result would be the same if we considered any of Matthews et al.’s (1991) announcement-proof equilibrium refinements in place of the neologism-proof refinement. We have focused on the neologism-proof equilibrium concept for simplicity of presentation, not to advocate for one solution concept over another. All of these refinements share similar intuition.

Some moderately spiteful individuals may pool with the friendly types.

In fact, prior knowledge that \(\lambda _j=0\) is both necessary and sufficient for \(\beta ^*=0\).

Pre-play communication in public goods game actually increases generosity (cf. Sally 1995), in contrast to the dictator game, where it serves as a substitute. An important factor may be that players in the public goods game can both send and receive messages before making their contribution. Andreoni and Rao (2011)’s study of the dictator game finds that sending a message serves as a substitute for giving, but receiving a message actually increases giving. Our model does not explain why receiving a message might systematically stimulate generosity.