Central to Guala's target article is the claim that experimental studies of costly punishment should not be interpreted as evidence for the existence of costly punishment outside the lab, but at best as evidence for the existence of strong motivations to punish those who have behaved antisocially. In most field settings, however, these motivations are likely to manifest in lower or zero-cost behaviors like ridicule, ostracism, and gossip. We agree with this point and highlight the specific role played by gossip as a ubiquitous form of low-cost punishment prevalent in all known human societies. Indeed, Dunbar (Reference Dunbar2004) estimates that gossip constitutes 65% of all spoken communication.

We argue that gossip – the sharing of evaluative information about an absent third party – is a widespread and highly effective form of punishment found in field settings (Dunbar Reference Dunbar1996/1998) that alleviates the need for costlier forms of punishment. Gossip promotes cooperation in groups in two primary ways: (1) by spreading reputational information that warns group members about a transgressor, leading them to avoid or ostracize the transgressor; and (2) by increasing reputational incentives that deter individuals from behaving antisocially (Beersma & van Kleef, in press; Feinberg et al. Reference Feinberg, Willer, Stellar and Keltner2011; Willer et al. Reference Willer, Feinberg, Irwin, Schultz, Simpson, Hitlin and Vaisey2010).

Recent research finds that the social psychological dynamics driving gossip correspond quite well with the motives revealed by experimental research on costly punishment. In a series of studies, Feinberg et al. (Reference Feinberg, Willer, Stellar and Keltner2011) demonstrate that gossip is driven by the same negative affective response that underpins costly punishment. After witnessing a target behave selfishly in a social dilemma situation, observers showed heightened levels of negative affect (e.g., frustration, annoyance) and physiological arousal, both of which were reduced by passing on reputational information to the transgressor's future interaction partner. A subsequent study showed that participants would gossip even when it required investing their own earnings to do so. Akin to altruistic punishment findings, these results suggest that when individuals detect the presence of defectors in the environment, they experience a strong motivation to share reputational information with other group members, even when doing so is costly. Additional research has found gossip deters antisocial behavior; when given the opportunity to behave selfishly in a social dilemma, individuals behaved more prosocially if they knew an observer was likely to gossip about them (Beersma & van Kleef, in press; see also Dunbar Reference Dunbar1996/1998; 2004; Piazza & Bering Reference Piazza and Bering2008a; Sommerfeld et al. Reference Sommerfeld, Krambeck, Semmann and Milinski2007).

Whereas Guala emphasizes that the anthropological evidence fails to show robust patterns of costly punishment in the field, there is substantial cross-cultural evidence for the prevalence of gossip outside the lab. Evidence that gossip serves as a mechanism for maintaining cooperation has been demonstrated in small societies in Mexico, Polynesia, and Fiji, to name a few (Arno Reference Arno1980; Besnier Reference Besnier1989; Haviland Reference Haviland1977). It is sensible that gossip would be so widely used in small egalitarian societies because of its efficiency, effectively promoting cooperation at minimal cost. The small size of these societies means that all members know one another, ensuring that information can potentially spread to all group members and recipients of gossip know and potentially interact with the target. Additionally, in small societies, the spread of negative reputational information has a significantly greater impact on transgressors, with each individual person hearing of one's negative reputation representing a larger proportion of the group aware of the transgression. Moreover, gossip's low cost alleviates potential second-order free-rider problems that more costly punishment behaviors typically face.

Because of its effectiveness and low cost, we should expect gossip to be a more common response to the observation of antisocial behavior than more costly forms of punishment. This notion is consistent with evidence suggesting that costly punishment may become limited in environments where indirect reciprocity or reputational information offers a cheaper means of social control (Rockenbach & Milinski Reference Rockenbach and Milinski2006). That said, the fact that gossip is a more efficient tool of punishment in most settings does not rule out the possibility of more costly punishment in situations where gossip is impractical or ineffective.

Guala views gossip as a costless form of punishment, and we agree that its low-cost nature is likely critical to its prevalence. But the costs and benefits of gossip remain unclear and deserve future study. Gossip entails risks of retaliation and reputation loss. At the same time, it is also possible that gossip could offer benefits to the gossiper (Willer Reference Willer2009; Willer et al. Reference Willer, Feinberg, Irwin, Schultz, Simpson, Hitlin and Vaisey2010). Passing on reputational information may lead to a variety of possible benefits: (1) deterring antisocial behavior directed towards the gossiper by communicating that he or she will readily spread information about antisocial behavior; (2) improving status by advertising the extensiveness of the gossiper's connections in the group's social network (Cheng et al. Reference Cheng, Fournier and Di Domenico2007); and (3) advertising the gossiper's prosociality, thereby making him or her an attractive, trustworthy partner. Future research is needed to better understand the magnitude of costs and benefits associated with gossip and how these might vary across different contexts.