Review of Primate Cognition Research

Collaborative open science as a way to reproducibility and new insights in primate cognition research

We’ve submitted this review paper for publication. Find the PsyArXiv preprint here.


A widely held view within the field of primate cognition is that research is dominated by work with a small number of species conducted at a few sites. Another common conjecture is that primate cognition studies are characterized by notoriously small sample sizes. Small sample sizes present an obstacle to obtaining precise, reliable measures of ability, which are the basis for quantitative comparisons between species. To test these intuitions, we conducted a systematic review of primate cognition research published between 2014 and 2019 to quantify the extent of this problem. Our survey will appear as part of the special issue ‘reproducibility crisis and ways to overcome it’ in the Japanese Psychological Review.

Our review shows that the surveyed 574 primate cognition studies have a median sample size of just 7 individuals. Less than 15% of primate species were studied at all in this period (the studied species are highlighted in black in the above chronogram) and only 19% of studies included more than one species. Further, the species that were studied varied widely in how much research attention they received (the size of the points in the chronogram is proportional to the number of studies for each tested species), partly because a small number of test sites contributed most of the studies.

These results suggest that the generalizability of primate cognition studies may be severely limited. Based on this analysis, we outline key limitations of the field, highlight the importance of large-scale collaboration in primate cognition research, summarize the goals of ManyPrimates, report on the current state of the project, and suggest directions for the future.