Povinelli and colleagues ask whether chimpanzees can understand the concept of weight, answering with a resounding ‘‘no’’. They justify their answer by appeal to over thirty previously unpublished experiments. I here evaluate in detail Povinelli’s arguments against his targets, questioning the assumption that such comparative questions will be resolved with an unequivocal ‘‘yes’’ or ‘‘no’’.

Primatologists generally agree that monkeys lack higher-order intentional capacities related to theory of mind. Yet the discovery of the so-called "mirror neurons" in monkeys suggests to many neuroscientists that they have the rudiments of intentional understanding. Given a standard philosophical view about intentional understanding, which requires higher-order intentionahty, a paradox arises. Different ways of resolving the paradox are assessed, using evidence from neural, cognitive, and behavioral studies of humans and monkeys. A decisive resolution to the paradox requires substantial additional empirical (...) work and perhaps a rejection of the standard philosophical view. (shrink)

In a dynamic world, mechanisms allowing prediction of future situations can provide a selective advantage. We suggest that memory systems differ in the degree of flexibility they offer for anticipatory behavior and put forward a corresponding taxonomy of prospection. The adaptive advantage of any memory system can only lie in what it contributes for future survival. The most flexible is episodic memory, which we suggest is part of a more general faculty of mental time travel that allows us not only (...) to go back in time, but also to foresee, plan, and shape virtually any specific future event. We review comparative studies and find that, in spite of increased research in the area, there is as yet no convincing evidence for mental time travel in nonhuman animals. We submit that mental time travel is not an encapsulated cognitive system, but instead comprises several subsidiary mechanisms. A theater metaphor serves as an analogy for the kind of mechanisms required for effective mental time travel. We propose that future research should consider these mechanisms in addition to direct evidence of future-directed action. We maintain that the emergence of mental time travel in evolution was a crucial step towards our current success. (shrink)

Following the tradition of comparing humans with chimpanzees placed under unfavorable conditions, the authors suggest many uniquely human technological abilities. However, chimpanzees use spontaneously tools in nature to achieve many different goals demonstrating technological skills and reasoning contradicting the authors contrast. Chimpanzees and humans develop skills through the experiences faced during their upbringing and neglecting this leads to fake conclusions.

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)