Conwy Lloyd Morgan (1852–1936) is widely regarded as the father of modern comparative psychology. Yet, Morgan initially had significant doubts about whether a genuine science of comparative psychology was even possible, only later becoming more optimistic about our ability to make reliable inferences about the mental capacities of non-human animals. There has been a fair amount of disagreement amongst scholars of Morgan’s work about the nature, timing, and causes of this shift in Morgan’s thinking. We argue that Morgan underwent two (...) quite different shifts of attitude towards the proper practice of comparative psychology. The first was a qualified acceptance of the Romanesian approach to comparative psychology that he had initially criticized. The second was a shift away from Romanes’ reliance on systematizing anecdotal evidence of animal intelligence towards an experimental approach, focused on studying the development of behaviour. We emphasize the role of Morgan’s evolving epistemological views in bringing about the first shift – in particular, his philosophy of science. We emphasize the role of an intriguing but overlooked figure in the history of comparative psychology in explaining the second shift, T. Mann Jones, whose correspondence with Morgan provided an important catalyst for Morgan’s experimental turn, particularly the special focus on development. We also shed light on the intended function of Morgan’s Canon, the methodological principle for which Morgan is now mostly known. The Canon can only be properly understood by seeing it in the context of Morgan’s own unique experimental vision for comparative psychology. (shrink)

Physical cognition involves a host of cognitive abilities that enable understanding and manipulation of the physical world. Corvids, the bird family that includes crows, ravens and jays, are renowned for their cognitive abilities, but still little is known about their folk physics. This thesis explores the origins of physical cognition in corvids by investigating its mechanisms, development,fitness value and phylogeny in a wide context that includes theoretical and empirical studies.String pulling is a valuable paradigm for addressing these questions. Many animals (...) can pull a string with food attached to its end, but uncovering the cognitive abilities involved in this behaviour requires further testing. Paper I reviews the string-pulling paradigm, which is one of the oldest tests of animal cognition.It is a highly suitable test for species comparisons, socio-ecological correlations, and phylogenetic questions. Paper II tests several corvids, apes and peafowl on a string-pulling task where the first pulls do not result in the food moving closer. Despite the absence of such visual feedback, most subjects pulled strings in completely, although corvids appeared to choose randomly.Tool use is the archetypical example of physical cognition. Many corvids are remarkably adept at using tools in experimental settings. Paper III reviews animal tool use in general. It is now clear that customary tool-using species do not necessarily outperform their non-tool-using relatives on tests of physical cognition. For corvids that frequently use tools in the wild, such as New Caledonian crows and‘Alalā, tool use appears to have a significant fitness value and may have resulted in morphological adaptations. Paper IV describes a novel tool-use mode in New Caledonian crows. They inserted sticks into objects and then moved away,thereby transporting both. One crow could not grasp the target object, which suggests that such insert-and-transport tool use facilitates control over unwieldy objects. Paper V briefly argues that some corvids have shown the ability to make novel causal interventions, although this question should be addressed in a clearer theoretical framework that makes testable predictions.Sensorimotor cognition is a set of fundamental cognitive abilities that enables the integration of sensory and motor information into practical behaviour. It underlies much of corvid physical cognition. Paper VI investigates the development of sensorimotor cognition in ravens. Their skills developed rapidly and exceeded those of some mammals. They reached the same final sensorimotor stage as great apes, albeit at a markedly accelerated rate. The propensity of corvids to cache objects was investigated in Paper VII. Ravens, which often cache food,frequently cached objects, but surprisingly at similar rates as non-food-caching jackdaws. New Caledonian crows mostly cached objects that resembled functional tools.Anthropomorphism is the attribution of human traits to animals. Fear of mistakenly anthropomorphising animals has resulted in biased principles and an uneven burden of proof, which may hinder scientific progress more than it is supposed to offer protection against making mistakes. Cognitive zoology should not be misguided by overcompensating for such potential pitfalls. (shrink)