The importance of working memory updating in the Prisoner's dilemma

Memory as a cognitive requirement for reciprocal cooperation

Memory has evolved to guide our decisions in the present and to prepare us for future interactions with the environment. Within the social domain, memory can help to decide with whom to cooperate. This provides a unique opportunity to study memory from a functional perspective. Although several lines of research have demonstrated that many forms of reciprocal cooperation require memory, most of the research does not support the assumption of a highly specialized cheater-detection module that specifically serves to promote the detection of uncooperative interaction partners. Instead, the literature supports the flexible recruitment of domain-general guessing and memory mechanisms that serve to continuously predict the future behavior of others based on situational and person-specific factors and use violations of these expectations to update the predictive models of who can be trusted to cooperate in reciprocal interactions.

Limited memory optimizes cooperation in social dilemma experiments

Cooperation is one of the key collective behaviours of human society. Despite discoveries of several social mechanisms underpinning cooperation, relatively little is known about how our neural functions affect cooperative behaviours. Here, we study the effect of a main neural function, working-memory capacity, on cooperation in repeated Prisoner's Dilemma experiments. Our experimental paradigm overcomes the obstacles in measuring and changing subjects' working-memory capacity. We find that the optimal cooperation level occurs when subjects remember two previous rounds of information, and cooperation increases abruptly from no memory capacity to minimal memory capacity. The results can be explained by memory-based conditional cooperation of subjects. We propose evolutionary models based on replicator dynamics and Markov processes, respectively, which are in good agreement with experimental results of different memory capacities. Our experimental findings differ from previous hypotheses and predictions of existent models and theories, and suggest a neural basis and evolutionary roots of cooperation beyond cultural influences.

Behavioural Isomorphism, Cognitive Economy and Recursive Thought in Non-Transitive Game Strategy

Game spaces in which an organism must repeatedly compete with an opponent for mutually exclusive outcomes are critical methodologies for understanding decision-making under pressure. In the non-transitive game rock, paper, scissors (RPS), the only technique that guarantees the lack of exploitation is to perform randomly in accordance with mixed-strategy. However, such behavior is thought to be outside bounded rationality and so decision-making can become deterministic, predictable, and ultimately exploitable. This review identifies similarities across economics, neuroscience, nonlinear dynamics, human, and animal cognition literatures, and provides a taxonomy of RPS strategy. RPS strategies are discussed in terms of (a) whether the relevant computations require sensitivity to item frequency, the cyclic relationships between responses, or the outcome of the previous trial, and (b) whether the strategy is framed around the self or other. The negative implication of this taxonomy is that despite the differences in cognitive economy and recursive thought, many of the identified strategies are behaviorally isomorphic. This makes it difficult to infer strategy from behavior. The positive implication is that this isomorphism can be used as a novel design feature in furthering our understanding of the attribution, agency, and acquisition of strategy in RPS and other game spaces.

Influence of weight status at 2 years on memory performance at 4-5 years of age

Background: Memory performance is a cognitive function that is affected by environmental, genetic and socioeconomic factors, as well as by weight status.Aim: To evaluate the association of weight status at 2 years of age with the memory performance of children at 4-5 years of age.Subjects and methods: A cross-sectional study that used baseline data (2012) and data from two follow-up periods (2014 and 2016) of the PREDI Cohort Study. Participants were mother-child pairs 4-5 years after delivery who were seen between July 2016 and August 2017. The children's memory performance was evaluated individually using a validated Brazilian instrument.Results: Of the 203 children included in the study, 117 (57.6%), 52 (25.6%) and 34 (16.8%) had low, moderate and high memory performance, respectively. After adjusting for potential confounders, children with a BMI > 85th percentile had 3.33-times higher odds of exhibiting lower memory performance at 4-5 years of age than those with a BMI ≤ 85th percentile. In addition to the children's BMI at 2 years of age, mother's education was another independent determinant of children's memory performance. There was a progressive increase in the odds of children having lower memory performance at 4-5 years of age as the mother's education decreased.Conclusion: Primary prevention of overweight and management of cognitive functions may be important strategies to improve the cognitive development of children in the future.

Crosstalk in concurrent repeated games impedes direct reciprocity and requires stronger levels of forgiveness

Direct reciprocity is a mechanism for cooperation among humans. Many of our daily interactions are repeated. We interact repeatedly with our family, friends, colleagues, members of the local and even global community. In the theory of repeated games, it is a tacit assumption that the various games that a person plays simultaneously have no effect on each other. Here we introduce a general framework that allows us to analyze “crosstalk” between a player’s concurrent games. In the presence of crosstalk, the action a person experiences in one game can alter the person’s decision in another. We find that crosstalk impedes the maintenance of cooperation and requires stronger levels of forgiveness. The magnitude of the effect depends on the population structure. In more densely connected social groups, crosstalk has a stronger effect. A harsh retaliator, such as Tit-for-Tat, is unable to counteract crosstalk. The crosstalk framework provides a unified interpretation of direct and upstream reciprocity in the context of repeated games.

Social interactions among people are often repeated, and yet it is assumed that simultaneous interactions are independent from one another. Here, Reiter and colleagues describe a conceptual framework where an action in one game can influence the decision in another.