Uncertainty in experts' judgments exposes the vulnerability of research reporting anecdotes on animals' cognitive abilities.

Expertise in science, particularly in animal behaviour, may provide people with the capacity to provide better judgments in contrast to lay people. Here we explore whether experts provide a more objective, accurate and coherent evaluation of a recently reported anecdote on Atlantic puffin (Fratercula arctica) "tool use" (recorded on video) which was published in a major scientific journal but was received with some scepticism. We relied on citizen science and developed a questionnaire to measure whether experts in ethology and ornithology and lay people agree or disagree on (1) the description of the actions that they observe (the bird takes a stick in its beak), (2) the possible goal of the action (nest-building or grooming) and (3) the intentional component of the action (the bird took the stick into its beak in order to scratch itself). We hypothesised that contrary to the lay people, experts are more critical evaluators that is they are more inclined to report alternative actions, like nest building, or are less likely to attributing goal-directedness to the action in the absence of evidence. In contrast, lay people may be more prone to anthropomorphise utilising a teleological and intentional stance. Alternatively, all three groups of subjects may rely on anthropomorphism at similar levels and prior expertise does not play a significant role. We found that no major differences among the evaluators. At the group levels, respondents were relatively uncertain with regard to the action of the bird seen on the video but they showed some individual consistency with regard to the description of the action. Thus, we conclude that paradoxically, with regard to the task our experts are typically not experts in the strict sense of the definition, and suggest that anecdotal reports should not be used to argue about mental processes.