The Influence of Non-Cognitive Factors on Cognitive Performance in American Crows (Corvus brachyrhynchos)

Abstract

The study of the animal mind is made both fascinating and frustrating in equal measure by the inherent elusiveness of the cognitive processes occurring within it. Animal cognition can only be inferred through experimentation, often conducted by presenting a problem under the assumption that successful solution indicates some degree or kind of cognitive capability in the animal. In this dissertation, I set out to theoretically and experimentally investigate the suite of factors that may lead even highly cognitively capable individuals to perform less well than expected during cognitive tasks. In Chapter 1, I present risk perception as a lens through which to view how we assess the cognitive abilities of animals. Here, I examine the existing evidence on how animals can and do respond to perceived risk with behavioral changes and use these findings to posit how risk may inhibit successful problem-solving. In Chapter 2, I turn to my study species, urban American crows (Corvus brachyrhynchos), to investigate how personality is connected to risk perception and thus interacts with individual cognitive task solution. Using measures of sensory process sensitivity – the extent to which behavior is affected by environmental stimuli – during food presentations to wild crows, I documented individual variation in sensitivity, but also age and stimulus-related patterns of sensitivity across individuals. Overall, juvenile crows were less sensitive than yearlings or adults to the presence of an experimental feeding apparatus in their environment. Additionally, crows that had first seen the apparatus as yearlings were more sensitive to subsequent modifications of the apparatus than those first encountering it as adults. Across ages, crows were sensitive to larger modifications to the apparatus (a thicker cord wrapped around it compared to a thinner one), but not sensitive to specific color modifications (a yellow cord compared to a brown one). Finally, in Chapter 3, I present an experiment testing whether individual sensitivity characteristics could explain the crows’ success in solving the relatively simple feeding problem of lifting a lid on a hole which had previously been uncovered. While sensitivity had no overall effect on success, the diversity of exploratory behaviors was related to solving the task. Together, these results are among the first investigations focused specifically on sensitivity in non-human animals, opening the door to further studies on how risk perception may underlie aspects of animal personality and in turn shedding light on the complex cognitive processes that have evolved in animal minds including our own.