Social norm complexity and past reputations in the evolution of cooperation

Fernando P. Santos, Francisco C. Santos & Jorge M. Pacheco
Nature volume 555, pages 242–245 (08 March 2018)

Abstract

Indirect reciprocity is the most elaborate and cognitively demanding of all known cooperation mechanisms, and is the most specifically human because it involves reputation and status. By helping someone, individuals may increase their reputation, which may change the predisposition of others to help them in future. The revision of an individual’s reputation depends on the social norms that establish what characterizes a good or bad action and thus provide a basis for morality. Norms based on indirect reciprocity are often sufficiently complex that an individual’s ability to follow subjective rules becomes important, even in models that disregard the past reputations of individuals, and reduce reputations to either ‘good’ or ‘bad’ and actions to binary decisions. Here we include past reputations in such a model and identify the key pattern in the associated norms that promotes cooperation. Of the norms that comply with this pattern, the one that leads to maximal cooperation (greater than 90 per cent) with minimum complexity does not discriminate on the basis of past reputation; the relative performance of this norm is particularly evident when we consider a ‘complexity cost’ in the decision process. This combination of high cooperation and low complexity suggests that simple moral principles can elicit cooperation even in complex environments.

The article is here.

Is Pulling the Lever Sexy? Deontology as a Downstream Cue to Long-Term Mate Quality

Mitch Brown and Donald Sacco
Journal of Social and Personal Relationships
November 2017

Abstract

Deontological and utilitarian moral decisions have unique communicative functions within the context of group living. Deontology more strongly communicates prosocial intentions, fostering greater perceptions of trust and desirability in general affiliative contexts. This general trustworthiness may extend to perceptions of fidelity in romantic relationships, leading to perceptions of deontological persons as better long-term mates, relative to utilitarians. In two studies, participants indicated desirability of both deontologists and utilitarians in long- and short-term mating contexts. In Study 1 (n = 102), women perceived a deontological man as more interested in long-term bonds, more desirable for long-term mating, and less prone to infidelity, relative to a utilitarian man. However, utilitarian men were undesirable as short-term mates. Study 2 (n = 112) had both men and women rate opposite sex targets’ desirability after learning of their moral decisions in a trolley problem. We replicated women’s preference for deontological men as long-term mates. Interestingly, both men and women reporting personal deontological motives were particularly sensitive to deontology communicating long-term desirability and fidelity, which could be a product of the general affiliative signal from deontology. Thus, one’s moral basis for decision-making, particularly deontologically-motivated moral decisions, may communicate traits valuable in long-term mating contexts.

The research is here.

Game Theory and Morality

Moshe Hoffman , Erez Yoeli , and Carlos David Navarrete
The Evolution of Morality
Part of the series Evolutionary Psychology pp 289-316

Here is an excerpt:

The key result for evolutionary dynamic models is that, except under extreme conditions, behavior converges to Nash equilibria. This result rests on one simple, noncontroversial assumption shared by all evolutionary dynamics: Behaviors that are relatively successful will increase in frequency. Based on this logic, game theory models have been fruitfully applied in biological contexts to explain phenomena such as animal sex ratios (Fisher, 1958), territoriality (Smith & Price, 1973), cooperation (Trivers, 1971), sexual displays (Zahavi, 1975), and parent–offspring conflict (Trivers, 1974). More recently, evolutionary dynamic models have been applied in human contexts where conscious deliberation is believed to not play an important role, such as in the adoption of religious rituals (Sosis & Alcorta, 2003 ), in the expression and experience of emotion (Frank, 1988 ; Winter, 2014), and in the use of indirect speech (Pinker, Nowak, & Lee, 2008).

 Crucially for this chapter, because our behaviors are mediated by moral intuitions and ideologies, if our moral behaviors converge to Nash, so must the intuitions and ideologies that motivate them. The resulting intuitions and ideologies will bear the signature of their game theoretic origins, and this signature will lend clarity on the puzzling, counterintuitive, and otherwise hard-to-explain features of our moral intuitions, as exemplified by our motivating examples.

In order for game theory to be relevant to understanding our moral intuitions and ideologies, we need only the following simple assumption: Moral intuitions and ideologies that lead to higher payoffs become more frequent. This assumption can be met if moral intuitions that yield higher payoffs are held more tenaciously, are more likely to be imitated, or are genetically encoded. For example, if every time you transgress by commission you are punished, but every time you transgress by omission you are not, you will start to intuit that commission is worse than omission.

The book chapter is here.

Moralized Rationality: Relying on Logic and Evidence in the Formation and Evaluation of Belief Can Be Seen as a Moral Issue

Ståhl T, Zaal MP, Skitka LJ (2016)
PLoS ONE 11(11): e0166332. doi:10.1371/journal.pone.0166332

Abstract

In the present article we demonstrate stable individual differences in the extent to which a reliance on logic and evidence in the formation and evaluation of beliefs is perceived as a moral virtue, and a reliance on less rational processes is perceived as a vice. We refer to this individual difference variable as moralized rationality. Eight studies are reported in which an instrument to measure individual differences in moralized rationality is validated. Results show that the Moralized Rationality Scale (MRS) is internally consistent, and captures something distinct from the personal importance people attach to being rational (Studies 1–3). Furthermore, the MRS has high test-retest reliability (Study 4), is conceptually distinct from frequently used measures of individual differences in moral values, and it is negatively related to common beliefs that are not supported by scientific evidence (Study 5). We further demonstrate that the MRS predicts morally laden reactions, such as a desire for punishment, of people who rely on irrational (vs. rational) ways of forming and evaluating beliefs (Studies 6 and 7). Finally, we show that the MRS uniquely predicts motivation to contribute to a charity that works to prevent the spread of irrational beliefs (Study 8). We conclude that (1) there are stable individual differences in the extent to which people moralize a reliance on rationality in the formation and evaluation of beliefs, (2) that these individual differences do not reduce to the personal importance attached to rationality, and (3) that individual differences in moralized rationality have important motivational and interpersonal consequences.

The article is here.