Comparing meta-analyses and preregistered multiple-laboratory replication projects.

Many researchers rely on meta-analysis to summarize research evidence. However, there is a concern that publication bias and selective reporting may lead to biased meta-analytic effect sizes. We compare the results of meta-analyses to large-scale preregistered replications in psychology carried out at multiple laboratories. The multiple-laboratory replications provide precisely estimated effect sizes that do not suffer from publication bias or selective reporting. We searched the literature and identified 15 meta-analyses on the same topics as multiple-laboratory replications. We find that meta-analytic effect sizes are significantly different from replication effect sizes for 12 out of the 15 meta-replication pairs. These differences are systematic and, on average, meta-analytic effect sizes are almost three times as large as replication effect sizes. We also implement three methods of correcting meta-analysis for bias, but these methods do not substantively improve the meta-analytic results.

Author Correction: Comparing meta-analyses and preregistered multiple-laboratory replication projects.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Extending the Cooperative Phenotype: Assessing the Stability of Cooperation across Countries.

This paper studies whether individual cooperation is stable across settings and over time. Involving more than 7,000 subjects on two different continents, this study documents positive correlation in cooperative behavior across economic games in Norway, Sweden, Austria, and the United States. The game measures also correlate with a tendency to make deontological judgments in moral dilemmas, and display of general trust toward strangers. Using time-variation in the data, we test whether temporal stability of behavior is similar in the United States and Norway, and find similar stability estimates for both the American and Norwegian samples. The findings here provide further evidence of the existence of a stable behavioral inclination toward prosociality - a "cooperative phenotype," as it has recently been termed. Also in line with previous research, we find that punishment and cooperation seem to be uncorrelated.