Decision-making process of whether to signal and the underlying cognitive processes.

Signaler psychology: Investigating computations underlying human cooperative communication

Human cooperative intentions are intrinsically hidden from other people: willingness to help, support important values, or abide by mutually binding norms are all confined to the mind. While people can verbally advertise their intentions, verbal communication from unknown others is often mistrusted because it can be easily faked. To lend credibility to their words, people advertise their cooperative intentions using symbolic, embroidered gestures that are associated with substantial costs. For instance, before striking a business deal, the proposing party might organize a lavish dinner with exclusive food to signal they plan to invest in a business relationship. In certain communities, becoming a gang member is associated with material and prestige benefits, but this membership is often conditioned on undergoing initiation associated with painful body modifications or violent acts. Likewise, many religious traditions promote cooperation between their members but mandate participation in time-consuming and sometimes dangerous rituals as a signal of true intentions. When the benefits of collective action are at stake, people may reliably signal their cooperative intentions by associating costs with their communicated message. However, while such costly signals of cooperative intentions are found across human societies, it is puzzling why people lacking cooperative intentions do not perform the costly gesture and then just free-ride on the collective effort of their partners.

We propose that the effectiveness of costly signals is facilitated by the specific architecture of the human mind. Specifically, we suggest that automatic cognitive processes that compute costly signals' utility rely on biased cost and benefit estimations of cooperative signals. The intuitive processes generate a parameter space where uncommitted individuals perceive the utility of increasingly costly signals as negative, deterring them from joining and free-riding the collective effort. However, this proposition has not been empirically tested, leaving a critical gap in our understanding of fundamental aspects of human communication.

Signaler Psychology is a three-year project (2023-2025) funded by the Czech Science Foundation.

The Team

Martin Lang

Principal Investigator

Eva Kundtová Klocová

Senior Researcher

Katarína Čellarová

Post-doctoral Researcher

Alexandra Ružičková

Master Researcher

Radim Chvaja

Expert collaborator

Research Outpus

Estimated costs and benefits of participation in an extreme ritual in Mauritius

Humans often participate in physically harmful and demanding rituals with no apparent material benefits. While such behaviors have been traditionally explained using the lens of costly signaling theory, we question whether the canonical theory can be applied to the case of human cooperative signals and introduce a modification of this theory based on differential cost and benefit estimation. We propose that along with cooperative benefits, committed members also believe in supernaturally induced benefits, which motivate participation in extreme rituals and stabilize their effects on cooperative assortment. Using Thaipusam Kavadi as a prototypical costly ritual, we recruited Tamil (ingroup) and Christian (outgroup) participants in Mauritius (N = 385) and asked them to assess the cost and benefits of Kavadi participation or hiking. We found that ingroup participants estimated material costs as larger than outgroups, physical costs as lower, and benefits as larger. These findings suggest that estimated costs may vary based on their modality and cultural expectations (e.g. Kavadi participants are not supposed to show pain), while believed supernaturally induced benefits were consistently larger in ingroups compared to outgroups. We conclude that differential estimation of ritual benefits, not costs, are key to the persistence of extreme rituals and their function in the assortment of committed members, underscoring the role of differential estimation in the cognitive computation of signal utility.