How group identification distorts beliefs

This paper investigates how group identification distorts people’s beliefs about the ability of their peers in social groups. We find that experimentally manipulated identification with a randomly composed group leads to overconfident beliefs about fellow group members’ performance on an intelligence test. This result cannot be explained by individual overconfidence, i.e., participants overconfident in their own skill believing that their group performed better because of them, as this was ruled out by experimental design. Moreover, we find that participants with stronger group identification put more weight on positive signals about their group when updating their beliefs. These in-group biases in beliefs can have important economic consequences when group membership is used to make inference about an individual’s characteristics as, for instance, in hiring decisions

The Evolution of Facultative Conformity Based on Similarity

Conformist social learning can have a pronounced impact on the cultural evolution of human societies, and it can shape both the genetic and cultural evolution of human social behavior more broadly. Conformist social learning is beneficial when the social learner and the demonstrators from whom she learns are similar in the sense that the same behavior is optimal for both. Otherwise, the social learner's optimum is likely to be rare among demonstrators, and conformity is costly. The trade-off between these two situations has figured prominently in the longstanding debate about the evolution of conformity, but the importance of the trade-off can depend critically on the flexibility of one's social learning strategy. We developed a gene-culture coevolutionary model that allows cognition to encode and process information about the similarity between naive learners and experienced demonstrators. Facultative social learning strategies that condition on perceived similarity evolve under certain circumstances. When this happens, facultative adjustments are often asymmetric. Asymmetric adjustments mean that the tendency to follow the majority when learners perceive demonstrators as similar is stronger than the tendency to follow the minority when learners perceive demonstrators as different. In an associated incentivized experiment, we found that social learners adjusted how they used social information based on perceived similarity, but adjustments were symmetric. The symmetry of adjustments completely eliminated the commonly assumed trade-off between cases in which learners and demonstrators share an optimum versus cases in which they do not. In a second experiment that maximized the potential for social learners to follow their preferred strategies, a few social learners exhibited an inclination to follow the majority. Most, however, did not respond systematically to social information. Additionally, in the complete absence of information about their similarity to demonstrators, social learners were unwilling to make assumptions about whether they shared an optimum with demonstrators. Instead, social learners simply ignored social information even though this was the only information available. Our results suggest that social cognition equips people to use conformity in a discriminating fashion that moderates the evolutionary trade-offs that would occur if conformist social learning was rigidly applied

Coordination on networks: does topology matter?

Effective coordination is key to many situations that affect the well-being of two or more humans. Social coordination can be studied in coordination games between individuals located on networks of contacts. We study the behavior of humans in the laboratory when they play the Stag Hunt game - a game that has a risky but socially efficient equilibrium and an inefficient but safe equilibrium. We contrast behavior on a cliquish network to behavior on a random network. The cliquish network is highly clustered and resembles more closely to actual social networks than the random network. In contrast to simulations, we find that human players dynamics do not converge to the efficient outcome more often in the cliquish network than in the random network. Subjects do not use pure myopic best-reply as an individual update rule. Numerical simulations agree with laboratory results once we implement the actual individual updating rule that human subjects use in our laboratory experiments

Disaggregated social learnings strategies in opaque treatments from experiment 2.

<p>We placed each social learner in one of four categories. A social learner who always followed the minority choice among demonstrators was a “Min” type. One who always followed the majority was a “Maj” type. One who always chose left or always chose right was a “U” type (Unconditional). For the social learners who did not fall into these three categories, we estimated the social learning function of each. Specifically, let <i>Y</i>_<i>jk</i> ∈ {0, 1} indicate if social learner <i>k</i> chose left in block <i>j</i>, and let <i>x</i>_<i>j</i> be the centered proportion of demonstrators choosing left. We estimated by fitting <i>P</i>(<i>Y</i>_<i>jk</i> = 1) = (exp{<i>β</i>_<i>k</i> <i>x</i>_<i>j</i>})/(1 + exp{<i>β</i>_<i>k</i> <i>x</i>_<i>j</i>}) via maximum likelihood. Panels <b>A</b> and <b>B</b> show the distributions over types for the two opaque treatments with data pooled over discordant and concordant blocks. Gray bars show estimates significant at the 5% level. Given multiple tests, we expect two to three significant values by chance in each panel. Social learners who followed the minority (Min) or majority (Maj) and social learners with extreme values of (e.g. ) clearly responded to social information. The rest did not.</p

Evolution of link type by cost of obtaining information.

<p>Links between two cooperators are shaded blue, links between two defectors are shaded solid red, and mixed links are shaded light red. Links between two cooperators displace other link types almost completely in the free information treatment (a). Links among two defectors displace the other link types almost completely in the high-cost treatment (c). The low-cost treatment has either cooperator or defector links, depending on the final state of the network (b).</p

Total wealth in the population by period as a function of the cost required to discover information on partners.

<p>Participants start with an initial endowment of points each.</p

Proportion of -choices as a function of the fraction of neighbors that chose in the previous period.

<p>Dashed line at two thirds: at the left of the dashed line a myopic best replier chooses with probability zero; at the right of the dashed line a myopic best replier chooses with probability one.</p

Proportion of -choices by network topology.

<p>Proportions are aggregated over all sessions and periods in A, and over session in B.</p

Average number of neighbors by period and treatment (cost of information).

<p>The grey area plots the 95% CI for the cost = 0 treatment.</p