Participant recruitment methods and statistical reasoning performance

Optimal Bayesian reasoning performance has reportedly been elusive, and a variety of explanations have been suggested for this situation. In a series of experiments, it is demonstrated that these difficulties with replication can be accounted for by differences in participant-sampling methodologies. Specifically, the best performances are obtained with students from top-tier, national universities who were paid for their participation. Performance drops significantly as these conditions are altered regarding inducements (e.g., using unpaid participants) or participant source (e.g., using participants from a second-tier, regional university). Honours-programme undergraduates do better than regular undergraduates within the same university, paid participation creates superior performance, and top-tier university students do better than students from lower ranked universities. Pictorial representations (supplementing problem text) usually have a slight facilitative effect across these participant manipulations. These results indicate that studies should take account of these methodological details and focus more on relative levels of performance rather than absolute performance.     

Lewis' Strawman

In a survey of his views in the philosophy of mind, David Lewis criticizes much recent work in the field by attacking an imaginary opponent, 'Strawman'. His case against Strawman focuses on four central theses which Lewis takes to be widely accepted among contemporary philosophers of mind. The theses concern (1) the language of thought hypothesis and its relation to folk-psychology, (2) narrow content, (3) de se content, and (4) rationality. We respond to Lewis, arguing (amongst other things) that he underestimates Strawman's theoretical resources in a variety of important ways.     

The role of nonlinguistic stimuli and semantic relations in children's acquisition of grammatical utterances

Eighteen children, randomly assigned to one of six conditions, were trained in the use of two-word subject-verb (e.g. “mommy go”) utterances. The groups differed in (1) the number of different semantic relations theoretically underlying the subject-verb utterances on which the children were trained, and (2) the extent to which these semantic relations were associated with nonlinguistic events. The results indicated that the children acquired the subject-verb utterance forms more readily when they were also exposed to the events to which the utterances actually referred. Provided that the subject-verb utterances were related to ongoing events, the number of relations “underlying” these utterances did not appear critical. These results suggest that the child's acquisition of novel and grammatical utterances describing nonlinguistic stimuli highly similar to those in his natural environment are amenable to experimental control.     

The relation between size and apparent heaviness

Attention, Perception, & Psychophysics - A formula for the size-weight illusion was derived from the Stevens and Rubin (1970) finding that heaviness functions form a family of power functions...     

The flip side of the other‐race coin: They all look different to me

Poorer recognition of other‐race faces than own‐races faces has been attributed to a problem of discrimination (i.e., telling faces apart). The conclusion that ‘they all look the same to me' is based on studies measuring the perception/memory of highly controlled stimuli, typically involving only one or two images of each identity. We hypothesized that such studies underestimate the challenge involved in recognizing other‐race faces because in the real world, an individual's appearance varies in a number of ways (e.g., lighting, expression, hairstyle), reducing the utility of relying on pictorial cues to identity. In two experiments, Caucasian and East Asian participants completed a perceptual sorting task in which they were asked to sort 40 photographs of two unfamiliar identities into piles such that each pile contained all photographs of a single identity. Participants perceived more identities when sorting other‐race faces than own‐race faces, both when sorting celebrity (Experiment 1) and non‐celebrity (Experiment 2) faces, suggesting that in the real world, ‘they all look different to me'. We discuss these results in the light of models in which each identity is represented as a region in a multidimensional face space; we argue that this region is smaller for other‐race than own‐race faces.