Advertising cooperative phenotype through costly signals facilitates collective action

Abstract

Around the world, people engage in practices that involve self-inflicted pain and apparently wasted resources. Researchers theorized that these practices help stabilize within-group cooperation by assorting individuals committed to collective action. While this proposition was previously studied using existing religious practices, we provide a controlled framework for an experimental investigation of various predictions derived from this theory. We recruited 372 university students in the Czech Republic who were randomly assigned into either a high-cost or low-cost condition and then chose to play a public goods game (PGG) either in a group that wastes money to signal commitment to high contributions in the game or to play in the group without such signals. We predicted that cooperators would assort in the high-cost revealed group and that, despite these costs, they would contribute more to the common pool and earn larger individual rewards over five iterations of PGG compared with the concealed group and participants in the low-cost condition. The results showed that the assortment of cooperators was more effective in the high-cost condition and translated into larger contributions of the remaining endowment to the common pool, but participants in the low-cost revealed group earned the most. We conclude that costly signals can serve as an imperfect assorting mechanism, but the size of the costs needs to be carefully balanced with potential benefits to be profitable.

The role of costly commitment signals in assorting cooperators during intergroup conflict

“…For comparison, while the probability of selecting the revealed group in the high cost condition in Lang et al' study (2022) was 57% for cooperators, it was only 38% in the current study. The prospect of multiple PGG rounds likely contributed to increasing the signal's reliability in the eyes of cooperators in the Lang et al (2022) study, while many cooperators in the current study would distrust the one-shot signal. Interestingly, the low cost signal successfully repelled participants with selfish strategies (only 14% chose the revealed group in the low cost condition).…”

“…These opportunity costs often serve as costs associated with ultra-cooperative groups (Iannaccone, 1992), yet it is unclear whether they may also reliably assort cooperators during intergroup conflict. From the game-theoretical perspective, including positive rather than negative costs should not affect the between-and within-group dynamics, but we wager that such a change might significantly impact signaler and receiver psychology (Lang et al, 2022;Soler, 2012). If these positive and negative costs would indeed differently motivate participants' gameplay and, especially, the decision to sacrifice and hurt the outgroup, these results could help us better understand how some ultra-cooperative groups may motivate their members to commit self-sacrificial violent acts (Iannaccone & Berman, 2006).…”

“…For example, using a Public Goods Game (PGG) where people could choose to send costly signals of cooperative intentions, we previously found that cooperators were more likely (compared to selfish individuals) to choose a costly signal to communicate their commitment to the collective cooperative action. Moreover, choosing to send a costly signal was associated with larger contributions to the common pool in PGG (Lang et al, 2022).…”

“…Furthermore, we examined whether sending costly signals also predicts pro-group sacrifice in the form of paying to hurt the outgroup (which is beneficial to the ingroup). To this end, we used an experimental framework where participants are first scored on their cooperative strategies, randomly divided into high and low cost conditions (cost manipulation), and then asked to choose a group to play a PGG with (Lang et al, 2022). In both cost conditions, participants choose between a group where people sacrifice part of their endowment to signal a willingness to send large amounts to the common pool (15% in the high cost and 2.5% in the low cost condition) and a group where such willingness is signaled only verbally.…”

Religious costly signal induces more trustworthiness than secular costly signal: A study of pilgrimage to Santiago de Compostela

“…The reviewed evidence suggests that costly religious signals reliably communicate trustworthiness to other co‐religionists, and that people can use this group‐specific form of communication to sustain cooperation and reciprocity with other members of religious communities. Interestingly, despite some supportive evidence from laboratory experiments (Lang et al., 2022), the sparse research conducted outside religious traditions suggests that costly commitment signalling may not be effective in real‐world secular contexts. First, using archival data on the survival of US 19th‐century utopian communes, Sosis and Bressler (2003) showed that while the frequency of costly group practices (taboos, collective rituals) was associated with commune longevity (presumably due to increased intra‐group trust and cooperation), this effect was higher in religious communes compared to secular communes.…”