cademic science is a culturally evolved social institution with formal rules, norms and conventions. However, in recent years, scientists have begun to examine the utility of even longstanding characteristics of this institution 1-3 . For example, it is now widely recognized that preferentially valuing positive over negative results can generate publication bias, which distorts the published literature 4,5 ; evaluating scientists based on their number of publications can cause a myopic focus on productivity at the expense of rigour 6 ; and rewarding scientists based on the prestige of the journal in which they publish may incentivize scientists to present their work in an overly positive light, submit low-quality papers to high-impact journals and engage in other questionable research practices [7][8][9][10][11][12] .The priority rule is a particularly longstanding scientific norm, in which individuals who are first to make discoveries receive disproportionate credit relative to all other individuals who provide solutions to the same problem 13,14 . Famously, Charles Darwin was motivated to publish his writings on evolution by means of natural selection in part because of a concern that he would lose priority to Alfred Russel Wallace, who had developed a similar idea. In his famous letter to Charles Lyell, Darwin proclaimed "I rather hate the idea of writing for priority, yet I certainly should be vexed if any one were to publish my doctrines before me" 15 . Rewards for priority take on various forms, including eponymy (that is, naming a scientific discovery after the scientist who discovered it), financial prizes (for example, the Nobel prize), an increased probability of publishing in high-impact journals, and better professional positions and speaking engagements 3,13,16,17 . Little research explicitly documents the career repercussions of losing a priority race (that is, getting scooped). However, one survey of physical and biological scientists found that over 60% of scientists reported being scooped at some point in their careers 18 , and a recent study among structural biologists found that scooped papers received 28% fewer citations and were 18% less likely to appear in a top-ten journal 19 . This suggests that scientists have significant incentives to compete over priority of discovery.Given its role as a major incentive, how does rewarding priority of discovery affect scientific inquiry? Rewards for priority can