Chimpanzee (Pan troglodytes) relational matching: playing by their own (analogical) rules

Chimpanzees (Pan troglodytes) have been known to exhibit rudimentary abilities in analogical reasoning (Flemming, Beran, Thompson, Kleider, & Washburn, 2008; Gillian, Premack, & Woodruff, 1981; Haun & Call, 2009; Thompson & Oden, 2000; Thompson, Oden, & Boysen, 1997). With a wide array of individual differences, little can be concluded about the species' capacity for analogies, much less their strategies employed for solving such problems. In this study, we examined analogical strategies in 3 chimpanzees using a 3-dimensional search task (e.g., Kennedy & Fragaszy, 2008). Food items were hidden under 1 of 2 or 3 plastic cups of varying sizes. Subsequently, chimpanzees searched for food under the cup of the same relative size in their own set of cups--reasoning by analogy. Two chimpanzees initially appeared to fail the first relational phase of the task. Meta-analyses revealed, however, that they were instead using a secondary strategy not rewarded by the contingencies of the task--choosing on the basis of the same relative position in the sample. Although this was not the intended strategy of the task, it was nonetheless analogical. In subsequent phases of the task, chimpanzees eventually learned to shift their analogical reasoning strategy to match the reward contingencies of the task and successfully choose on the basis of relative size. This evidence not only provides support for the analogical ape hypothesis (Thompson & Oden, 2000), but also exemplifies how foundational conceptually mediated analogical behavior may be for the chimpanzee.     

V—Naive Realism and Experiential Evidence

I describe a naive realist conception of perceptual knowledge, which faces a challenge from the idea that normal perceivers and brains-in-vats have equally justified perceptual beliefs. I defend the naive realist position from Nicholas Silins's recent version of this challenge. I argue that Silins's main objection fails, and that the naive realist understanding of perceptual knowledge can be reconciled with the idea that brains-in-vats have justified perceptual beliefs.     

Young citizens in Hong Kong: obedient,active and patriotic?

There are multiple ways of understanding citizenship: as a status conferred by a nation state, a personal identity constructed in response to particular circumstances or a social identity developed out of group membership. These are not mutually exclusive categories: an individual may experience “citizenships” that integrate these legal, personal and social identities. Yet how do young people who are not yet citizens understand what it means to be a citizen? In the present study, 15-year-old Hong Kong students were surveyed 2 years after the transition from colonial rule to Chinese sovereignty. They were asked to respond to a series of questions about citizenship responsibilities and the way they saw these reflected in ‘good citizens’. The results showed that students viewed citizenship responsibilities as multidimensional with reference to specific groups. They identified legal obligations related to civil authorities, personal obligations to support other members of the community and patriotic obligations to support the nation-state.     

Emotional expression on a profile: Feature height, mouth angle, and tilt

Profiles may vary in expression with changes in the height of the profile’s features, the mouth’s angle at the profile contour, and head tilt. In three experiments, we varied these factors. Features low on the profile, with mouths at an obtuse angle to the profile line and head tilted 15° forehead-forward, appear especially sad. High features with acute mouth angles suit forward, upright, and backward head tilts. Feature height, mouth angle, and head tilt on a profile are physical variables that can specify postures such as downcast heads and turned-down mouths, and thereby psychological factors. We point out alternative accounts of the height and tilt effects.     

Analogical reasoning in a capuchin monkey (Cebus apella)

Previous evidence has suggested that analogical reasoning (recognizing similarities among object relations when the objects themselves are dissimilar) is limited to humans and apes. This study investigated whether capuchin monkeys (Cebus apella) can use analogical reasoning to solve a 3-dimensional search task. The task involved hiding a food item under 1 of 2 or 3 plastic cups of different sizes and then allowing subjects to search for food hidden under the cup of analogous size in their own set of cups. Four monkeys were exposed to a series of relational matching tasks. If subjects reached criterion on these tasks, they were exposed to relational transfer tasks involving novel stimuli. Three of the monkeys failed to reach criterion on the basic relational matching tasks and therefore were not tested further. One monkey, however, revealed above-chance performance on a series of transfer tasks with 3 novel stimuli. This evidence suggests that contrary to previous arguments, a member of a New World monkey species can solve an analogical problem.     

Ellipses on the surface of a picture

Shapes on the surface of a perspective picture may be misperceived. Subjects picked a match for an ellipse depicting the circular top of a cylinder. The top was depicted as tilted forward from 5 degrees to 85 degrees, generating a series of ellipses on the picture surface. The matches were biased towards a circle over a wide range of midrange tilts, which suggests that, influenced by features of perspective, they were seen as in-between the shape on the surface and the shape they depicted.