Asymmetric cognitive learning mechanisms underlying the persistence of intergroup bias.

Intergroup bias, the tendency to favor ingroups and be hostile towards outgroups, underlies many societal problems and persists even when intergroup members interact and share experiences. Here we study the way cognitive learning processes contribute to the persistence of intergroup bias. Participants played a game with ingroup and outgroup bot-players that entailed collecting stars and could sacrifice a move to zap another player. We found that intergroup bias persisted as participants were more likely to zap outgroup players, regardless of their zapping behavior. Using a computational model, we found that this bias was caused by asymmetries in three learning mechanisms. Participants had a greater prior bias to zap out-group players, they learned more readily about the negative behavior of out-groups and were less likely to attribute the positive behavior of one out-group player to other out-group players. Our results uncover the way cognitive social learning mechanisms shape and confound intergroup dynamics.

Prosocial behavior in competitive fish: the case of the archerfish.

Humans are social creatures, demonstrate prosocial behaviors, and are sensitive to the actions and consequent payoff of others. This social sensitivity has also been found in many other species, though not in all. Research has suggested that prosocial tendencies are more pronounced in naturally cooperative species whose social structure requires a high level of interdependence and allomaternal care. The present study challenges this assumption by demonstrating, in a laboratory setting, that archerfish, competitive by nature, preferred targets rewarding both themselves and their tankmates, but only when the payoff was equal. With no tankmate on the other side of the partition, they exhibited no obvious preference. Finding evidence for prosocial behavior and negative responses to unequal distribution of reward to the advantage of the other fish suggests that in a competitive social environment, being prosocial may be the most adaptive strategy for personal survival, even if it benefits others as well.

The devil is in the task structure.

Conflicting evidence about how the brain processes social and individual learning stems from which type of information is presented as the primary source of knowledge during experiments.

The effect of co-actor group membership on the social inhibition of return effect.

Being part of a group is a crucial factor in human social interaction. In the current study we explored whether group membership affects reflexive automatic cognitive functioning, and specifically the social inhibition of return effect (SIOR; Welsh et al., 2005). SIOR is characterized by slower reaction times (RTs) to a location already searched by another agent. To examine whether group membership modulates SIOR, we recruited Muslim and Jewish students from the University of Haifa to perform a task with either an in-group member or an out-group member. Both IOR and SIOR were suggested to act as a foraging facilitator (Klein, 2000; Welsh et al., 2005). Accordingly, we predicted that the SIOR effect would be larger when performing the task with an in-group member than with an out-group member. The results confirmed our prediction by indicating that the co-actor's group membership modulated the SIOR effect. These findings are consistent with the notion that social factors play a critical role in producing the SIOR effect and provide a novel indication of the influence of social factors such as group membership on basic reflexive cognitive processes.

The Differential Impact of a Response's Effectiveness and its Monetary Value on Response-Selection.

While known reinforcers of behavior are outcomes that are valuable to the organism, recent research has demonstrated that the mere occurrence of an own-response effect can also reinforce responding. In this paper we begin investigating whether these two types of reinforcement occur via the same mechanism. To this end, we modified two different tasks, previously established to capture the influence of a response's effectiveness on the speed of motor-responses (indexed here by participants' reaction times). Specifically, in six experiments we manipulated both a response's 'pure' effectiveness and its outcome value (e.g., substantial versus negligible monetary reward) and measured the influence of both on the speed of responding. The findings strongly suggest that post action selection, responding is influenced only by pure effectiveness, as assessed by the motor system; thus, at these stages responding is not sensitive to abstract representations of the value of a response (e.g., monetary value). We discuss the benefit of distinguishing between these two necessary aspects of adaptive behavior namely, fine-tuning of motor-control and striving for desired outcomes. Finally, we embed the findings in the recently proposed Control-based response selection (CBRS) framework and elaborate on its potential for understanding motor-learning processes in developing infants.