Exponential authorship inflation in neuroscience and psychology from the 1950s to the 2020s.

Abstract

How many researchers does it take to publish a paper in top journals in neuroscience and psychology? Manually coding 42,580 papers spanning 1879-2021 from 32 journals, we examine the evolution of authorship size and its rate of change, and evaluate forces that drive the changes.We found that, starting from the 1950s, the average authorship size per paper in neuroscience and psychology has increased exponentially, growing by 50% and 31% over the last decade and reaching a record high of 10.4 and 4.8 authors in 2021, respectively. Single-authored papers have become a rarity today, particularly in primary research papers: 1.7% in neuroscience and 2.2% in psychology in the 2020s (vs. 5.7% and 11.2% in review papers). With the withering of sole authors rises a new type of authorship, group authors (e.g., a consortium). Group authorship was rare before 2000, but in 2019-2021 it appeared in 4.1% of papers in neuroscience, mostly in genetics, neuroimaging, and disease-outnumbering single-authored papers for the first timeand 0.7% in psychology, mostly in developmental and clinical research. The exponential inflation in authorship size could not be attributed to editorial behaviors in profit-oriented journals, but aligns with a hybrid epistemic-behavioral-cultural account-an account that integrates multidimensional factors, including increased research complexity, the benefits of collaboration, the rise of government-funded research, changing norms in authorship practices, and biased incentives in evaluation. These findings suggest troubling implications for research reproducibility, innovations, equity/diversity, and ethics, calling for policy deliberations to address potential negative ramifications.