Do wild New Caledonian crows (<Emphasis Type="Italic">Corvus moneduloides</Emphasis>) attend to the functional properties of their tools?

New Caledonian crows are the most proficient non-hominin tool manufacturers but the cognition behind their remarkable skills remains largely unknown. Here we investigate if they attend to the functional properties of the tools that they routinely use in the wild. Pandanus tools have natural barbs along one edge that enable them to function as hooking implements when the barbs face backwards from the working tip. In experiment 1 we presented eight crows with either a non-functional (‘upside-down’) or a functional pandanus tool in a baited hole. Four of the crows never flipped the tools. The behaviour of the four flipping birds suggested that they had a strategy of flipping a tool when it was not working. Observations of two of the eight crows picking up pandanus tools at feeding tables in the wild supported the lack of attention to barb direction. In experiment 2 we gave six of the eight crows a choice of either a barbed or a barbless pandanus tool. Five of the crows chose tools at random, which further supported the findings in experiment 1 that the crows paid little or no attention to the barbs. In contrast, a third experiment found that seven out of eight crows flipped non-functional stick tools significantly more than functional ones. Our findings indicate that the crows do not consistently attend to the presence or orientation of barbs on pandanus tools. Successful pandanus tool use in the wild seems to rely on behavioural strategies formed through associative learning, including procedural knowledge about the sequence of operations required to make a successful pandanus tool. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Reasoning about make-believe and hypothetical suppositions: Towards a theory of belief-contravening reasoning

The present study explores how suppositions which conflict with accepted beliefs are represented and reasoned about. Two studies test the predictions regarding the nature and developmental changes in children's ability to represent and reason about hypothetical or make-believe suppositions which violate their everyday knowledge and beliefs. In Study 1, 46 4th- and 5th-graders were introduced to a hand puppet, Freddy, who made claims inconsistent with generally accepted beliefs (e.g., “all dogs meow”) because he was pretending (Make-Believe Condition) or believed them (Hypothetical Condition). Participants were asked to think like Freddy and judge whether a conclusion (“There's a dog; does it meow?”) follows logically from the claim. In Study 2, 40 kindergarten (6-year-olds), 3rd–4th grade (10-year-olds), and college students were asked to represent belief contravening make-believe (pretend in a make-believe world that dogs meow) and hypothetical (imagine what the real world would be like if dogs meow) premises, evaluate conclusions of the premises (Rover is a dog, does Rover meow?) and make judgments about the attributes (growl, wag tail, purr, and eat mice) of the entity (a meowing dog) they created. The prediction that it would be easier to represent and reason from belief-contravening suppositions in the Make-Believe than Hypothetical conditions was confirmed in each study, although the two forms of reasoning were directly correlated (Study 2). The results were discussed in terms of the similarities (compartmentalization and integration) and differences (reconciliation) of processes involved in fancifully (make-believe) or seriously (hypothetical) representing and reasoning about belief-contravening suppositions.     

Keith Lehrer on Compatibilism

Keith Lehrer has been publishing on free will and compatiblism since 1960. Our concern here is to present an account of the development on his work on the subject.     

Navigating Comics II: Constraints on the Reading Order of Comic Page Layouts

Although readers typically believe that comic page layouts should be read following the left to right and down ‘Z‐path’ inherited from written language, several spatial arrangements can push readers to deviate from this order. These manipulations include separating panels from each other, overlapping one panel onto another, and using a long vertical panel to the right of a vertical column to ‘block’ a horizontal row. We asked participants to order empty panels in comic page layouts that manipulated these factors. All manipulations caused participants to deviate from the conventional Z‐path, and this departure was modulated by incremental changes to spatial arrangements: The more layouts deviated from a grid, the less likely participants were to use the Z‐path. Overall, these results reinforce that various constraints push comic readers to engage with panels in predictable ways, even when deviating from the traditional Z‐path of written language. Copyright © 2014 John Wiley & Sons, Ltd.