Another social science looks at itself Experimental economists have joined the reproducibility discussion by replicating selected published experiments from two top-tier journals in economics. Camerer et al. found that two-thirds of the 18 studies examined yielded replicable estimates of effect size and direction. This proportion is somewhat lower than unaffiliated experts were willing to bet in an associated prediction market, but roughly in line with expectations from sample sizes and P values. Science , this issue p. 1433

Here we provide further details on the replications, the estimation of standardized effect sizes and complementary replicability indicators, the implementation of the prediction markets and surveys, the comparison of prediction market beliefs, survey beliefs, and replication outcomes, the comparison of reproducibility indicators to experimental economics and the psychological sciences, and additional results and data for the individual studies and markets. The code used for the estimation of replication power, standardized effect sizes, all complementary replication indicators, and all results is posted at OSF (https://osf.io/pfdyw/). Replications Inclusion criteriaWe replicated 21 experimental studies in the social sciences published between 2010 and 2015 in Nature and Science. We included all studies that fulfilled our inclusion criteria for:(i) the journal and time period, (ii) the type of experiment, (iii) the subjects included in the experiment, (iv) the equipment and materials needed to implement the experiment, and (v) the results reported in the experiment. We did not exclude studies that had already been subject to a replication, as this could affect the representativity of the included studies. We define and discuss the five inclusion criteria below. Journal and time period: We included experimental studies published in Nature andScience between 2010 and 2015. The reason for focusing on these two journals is that they are typically considered the two most prestigious general science journals. Articles published in these journals are considered exciting, innovative, and important, which is also reflected in their high impact factors. * Number of observations; number of individuals provided in parenthesis. † Replicated; significant effect (p < 0.05) in the same direction as in original study. ‡ Statistical power to detect 50% of the original effect size r. § Relative standardized effect size. * Belief about the probability of replicating in stage 1 (90% power to detect 75% of the original effect size).† Predicted added probability of replicating in stage 2 (90% power to detect 50% of the original effect size) compared to stage 1. * Mean number of tokens (points) invested per transaction. † Mean number of shares bought or sold per transaction.

These first ten authors contributed equally to this work.

SignificanceBuilding on recent advancements in the assessment of psychological traits from digital footprints, this paper demonstrates the effectiveness of psychological mass persuasion—that is, the adaptation of persuasive appeals to the psychological characteristics of large groups of individuals with the goal of influencing their behavior. On the one hand, this form of psychological mass persuasion could be used to help people make better decisions and lead healthier and happier lives. On the other hand, it could be used to covertly exploit weaknesses in their character and persuade them to take action against their own best interest, highlighting the potential need for policy interventions.

Behavioral neuroscientists have shown that the neuropeptide oxytocin (OT) plays a key role in social attachment and affiliation in nonhuman mammals. Inspired by this initial research, many social scientists proceeded to examine the associations of OT with trust in humans over the past decade. To conduct this work, they have (a) examined the effects of exogenous OT increase caused by intranasal administration on trusting behavior, (b) correlated individual difference measures of OT plasma levels with measures of trust, and (c) searched for genetic polymorphisms of the OT receptor gene that might be associated with trust. We discuss the different methods used by OT behavioral researchers and review evidence that links OT to trust in humans. Unfortunately, the simplest promising finding associating intranasal OT with higher trust has not replicated well. Moreover, the plasma OT evidence is flawed by how OT is measured in peripheral bodily fluids. Finally, in recent large-sample studies, researchers failed to find consistent associations of specific OT-related genetic polymorphisms and trust. We conclude that the cumulative evidence does not provide robust convergent evidence that human trust is reliably associated with OT (or caused by it). We end with constructive ideas for improving the robustness and rigor of OT research.