Debates in animal cognition are frequently polarized between the romantic view that some species have human-like causal understanding and the killjoy view that human causal reasoning is unique. These apparently endless debates are often characterized by conceptual confusions and accusations of straw-men positions. What is needed is an account of causal understanding that enables researchers to investigate both similarities and differences in cognitive abilities in an incremental evolutionary framework. Here we outline the ways in which a three-dimensional model of causal (...) understanding fulfills these criteria. We describe how this approach clarifies what is at stake, illuminates recent experiments on both physical and social cognition, and plots a path for productive future research that avoids the romantic/killjoy dichotomy. (shrink)

In this paper I critically discuss and, in the end, reject Morgan’s Canon, a popular principle in comparative psychology. According to this principle we should always prefer explanations of animal behavior in terms of lower psychological processes over explanations in terms of higher psychological processes, when alternative explanations are possible. The validity of the principle depends on two things, a clear understanding of what it means for psychological processes to be higher or lower relative to each other and a justification (...) of a general preference for explanations that refer to lower psychological abilities. However, I argue that we cannot spell out the idea of a psychological scale in a way that claim is satisfied. I start with the discussion of different interpretations of the notion of a psychological scale. In Sect. 3, I discuss different possible strategies to justify any of those interpretations and argue that all of them fail. Finally, in Sect. 4, I generalize the argument for all possible interpretations of Morgan’s Canon and propose an alternative strategy: We should base our interpretations of animal behavior on more general principles such as evidential support and explanatory power, as followed in other scientific domains. (shrink)

In guarding against inferential mistakes, experimental comparative cognition errs on the side of underattributing sophisticated cognition to animals, or what I refer to as the underattribution bias. I propose eliminating this bias by altering the method of choosing the default, or null, hypothesis. Rather than choosing the most parsimonious null hypothesis, as is current practice, I argue for choosing the best-evidenced hypothesis. Doing so at once preserves the risk-controlling structure of the current statistical paradigm and introduces a sensitivity to probability-conferring (...) empirical and theoretical information. This analysis illustrates how values like parsimony can covertly shape statistical-experimental design and inference. (shrink)

Principles help comparative psychologists select from among multiple hypotheses that account for the data. Anthropomorphic principles select hypotheses that have the most human–animal similarities while anthropectic principles select hypotheses that have the most human–animal differences. I argue that there is no way for the comparative psychologist on their own to justify their selection of one principle over the other. However, the comparative psychologist can justify their selection of one principle over the other in virtue of being members of comparative psychology (...) as a community. As it turns out, though, this justifies both competing principles: the community benefits most from competition between the two principles so comparative psychologists are justified in implementing the principles by which they can best contribute to the competition. Thus, I argue that common arguments to unify principle implementation in comparative psychology are defeated by the conservative arguments to preserve and foster competition. (shrink)

Philosophers and psychologists make many different, seemingly incompatible parsimony claims in support of competing models of cognition in nonhuman animals. This variety of parsimony claims is problematic. Firstly, it is difficult to justify each specific variety. This problem is especially salient for Morgan's Canon, perhaps the most important variety of parsimony claimed. Secondly, there is no systematic way of adjudicating between particular claims when they conflict. I argue for a view of parsimony in comparative psychology that solves these problems, based (...) on Sober's view that parsimony claims are claims that one model is more plausible given background theory. (shrink)

Comparative psychology experiments typically test a null statistical hypothesis against an alternative. Coupled with Morgan’s canon, this is often taken to imply that the model positing the simpler psychological capacity should be treated as a ‘default’ that must be ruled out before any other model can be accepted. It has been posited that this practice neglects evidence. I argue that the problem is deeper, including the way it structures the evaluation of evidence that is considered; it frames model choice around (...) the acceptance or rejection of a default. I oppose this default framing in all its forms and develop an evidentialist alternative. Default framing fails to respect the difference between experimental statistical hypotheses and substantive hypotheses such as models. It is not actually supported by the use of null hypothesis significance testing (which I retain), it distorts the weighting of evidence, and it systematically biases practice. (shrink)

The theory-theory of human uniqueness posits that the capacity to theorize, in a way strongly analogous to theorizing in scientific practice, was a key innovation in the hominid lineage and was responsible for many of our unique cognitive traits. One of the central arguments that its proponents have used to support the claim that animals are not theorists, the logical problem, bears strong similarities to Hempel's theoretician's dilemma, which purports to show that theories are unnecessary. This similarity threatens to undermine (...) both the claim that theorizing serves a unique, adaptive role in human cognition and our ability to test for the presence of theories. I examine two historical responses to the theoretician's dilemma and argue that they open up strategies for experimentally testing for theoretical ability in other animals. (shrink)

Charles Darwin and C. Lloyd Morgan forward two influential principles of cognitive ethological inference that yield conflicting results about the extent of continuity in the cognitive traits of humans and other animals. While these principles have been interpreted as reflecting commitments to different senses of parsimony, in fact, both principles result from the same vera causa inferential strategy, according to which “We ought to admit no more causes of natural things, than such as are both true and sufficient to explain (...) their appearances”. Instead, the conflict stems from Darwin’s and Morgan’s views about the true causes of human psychology. Darwin holds a thoroughly Humean philosophy of the human mind, from which he infers significant continuity between human and animal minds. In contrast, Morgan argues that Humean cognitive mechanisms cannot account for a class of uniquely human behaviors, and therefore, he concludes that there is a significant discontinuity between human and animal cognition. This historical debate is informative for current controversies in comparative psychology. (shrink)

We evaluate a common reasoning strategy used in community ecology and comparative psychology for selecting between competing hypotheses. This strategy labels one hypothesis as a “null” on the grounds of its simplicity and epistemically privileges it as accepted until rejected. We argue that this strategy is unjustified. The asymmetrical treatment of statistical null hypotheses is justified through the experimental and mathematical contexts in which they are used, but these contexts are missing in the case of the “pseudo-null hypotheses” found in (...) our case studies. Moreover, statistical nulls are often not epistemically privileged in practice over their alternatives because failing to reject the null is usually a negative result about the alternative, experimental hypothesis. Scientists should eschew the appeal to pseudo-nulls. It is a rhetorical strategy that glosses over a commitment to valuing simplicity over other epistemic virtues in the name of good scientific and statistical methodology. (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)

Behavioural flexibility is often treated as the gold standard of evidence for more sophisticated or complex forms of animal cognition, such as planning, metacognition and mindreading. However, the evidential link between behavioural flexibility and complex cognition has not been explicitly or systematically defended. Such a defence is particularly pressing because observed flexible behaviours can frequently be explained by putatively simpler cognitive mechanisms. This leaves complex cognition hypotheses open to ‘deflationary’ challenges that are accorded greater evidential weight precisely because they offer (...) putatively simpler explanations of equal explanatory power. This paper challenges the blanket preference for simpler explanations, and shows that once this preference is dispensed with, and the full spectrum of evidence—including evolutionary, ecological and phylogenetic data—is accorded its proper weight, an argument in support of the prevailing assumption that behavioural flexibility can serve as evidence for complex cognitive mechanisms may begin to take shape. An adaptive model of cognitive-behavioural evolution is proposed, according to which the existence of convergent trait–environment clusters in phylogenetically disparate lineages may serve as evidence for the same trait–environment clusters in other lineages. This, in turn, could permit inferences of cognitive complexity in cases of experimental underdetermination, thereby placing the common view that behavioural flexibility can serve as evidence for complex cognition on firmer grounds. (shrink)