The influence of surface and edge-based visual similarity on object recognition

The role of 'visual similarity' has been emphasised in object recognition and in particular, for category-specific agnosias. [Laws and Gale, 2002] recently described a measure of pixel-level visual overlap for line drawings (Euclidean Overlap: EO[line]) that distinguished living and nonliving things and predicted normal naming errors and latencies ( [Laws et al., 2002]). Nevertheless, it is important to extend such analyses to stimuli other than line drawings. We therefore developed the same measure for greyscale versions of the same stimuli (EO[grey]), i.e., that contain shading and texture information. EO[grey], however, failed to differentiate living from nonliving things and failed to correlate with naming latencies to the greyscale images. By contrast, EO[line] did correlate with the naming latencies. This suggests that similarity of edge information is more influential than similarity of surface characteristics for naming and for categorically separating living and nonliving things (be they line drawings or greyscale images).     

Tacit knowledge as the unifying factor in evidence based medicine and clinical judgement

The paper outlines the role that tacit knowledge plays in what might seem to be an area of knowledge that can be made fully explicit or codified and which forms a central element of Evidence Based Medicine. Appeal to the role the role of tacit knowledge in science provides a way to unify the tripartite definition of Evidence Based Medicine given by Sackett et al: the integration of best research evidence with clinical expertise and patient values. Each of these three elements, crucially including research evidence, rests on an ineliminable and irreducible notion of uncodified good judgement.     

An early electrophysiological response associated with expertise in letter perception

Expertise with print is likely to optimize visual processes for recognizing characters of a familiar writing system. Although brain activations have been identified for words and letter strings in contrast with other stimuli, relatively little work has focused on the neural basis of single-letter perception. English readers and Chinese-English bilinguals participated in an ERP study and performed a 1-back identity judgment on Roman letters, Chinese characters, pseudofonts, and their string versions. The Chinese-English bilinguals showed an enhanced N170 for both Roman letters and Chinese characters relative to pseudofonts. For the non-Chinese readers, the N170 amplitude was larger for Roman letters relative to Chinese characters and pseudofonts. Our results suggest that changes in relatively early visual processes underlie expert letter perception.     

Belief-desire reasoning as a process of selection

Human learning may depend upon domain specialized mechanisms. A plausible example is rapid, early learning about the thoughts and feelings of other people. A major achievement in this domain, at about age four in the typically developing child, is the ability to solve problems in which the child attributes false beliefs to other people and predicts their actions. The main focus of theorizing has been why 3-year-olds fail, and only recently have there been any models of how success is achieved in false-belief tasks. Leslie and Polizzi (Inhibitory processing in the false-belief task: Two conjectures. Developmental Science, 1, 247-254, 1998) proposed two competing models of success, which are the focus of the current paper. The models assume that belief-desire reasoning is a process which selects a content for an agent's belief and an action for the agent's desire. In false belief tasks, the theory of mind mechanism (ToMM) provides plausible candidate belief contents, among which will be a 'true-belief.' A second process reviews these candidates and by default will select the true-belief content for attribution. To succeed in a false-belief task, the default content must be inhibited so that attention shifts to another candidate belief. In traditional false-belief tasks, the protagonist's desire is to approach an object. Here we make use of tasks in which the protagonist has a desire to avoid an object, about which she has a false-belief. Children find such tasks much more difficult than traditional tasks. Our models explain the additional difficulty by assuming that predicting action from an avoidance desire also requires an inhibition. The two processing models differ in the way that belief and desire inhibitory processes combine to achieve successful action prediction. In six experiments we obtain evidence favoring one model, in which parallel inhibitory processes cancel out, over the other model, in which serial inhibitions force attention to a previously inhibited location. These results are discussed in terms of a set of simple proposals for the modus operandi of a domain specific learning mechanism. The learning mechanism is in part modular--the ToMM--and in part penetrable--the Selection Processor (SP). We show how ToMM-SP can account both for competence and for successful and unsuccessful performance on a wide range of belief-desire tasks across the preschool period. Together, ToMM and SP attend to and learn about mental states.     

Putting some feeling into it--the conceptual and empirical relationships between the classic and emotional Stroop tasks: comment on Algom, Chajut, and Lev (2004)

D. Algom, E. Chajut, and S. Lev presented a series of definitional, conceptual, and empirical arguments in support of their conclusion that the classic and emotional Stroop effects are, in their words, "unrelated phenomena" (p. 336), such that the term emotional Stroop effect is a misnomer in reference to the relatively greater interference in ink color naming of emotional versus neutral words. These are strong claims. In this comment, the author critically examines each component of Algom et al.'s case and argues that, in fact, none of these components represents compelling evidence in support of their eventual conclusions.     

Pitch perception in children with autistic spectrum disorders

This study investigated the accuracy of musical pitch detection in children with autistic spectrum disorders as compared with typically developing children. Seventeen children on the autistic spectrum (M(age) =9.34, SD(age) =1.12) and 13 typically developing, chronological age-matched children (M(age) =9.13, SD(age) =1.68) took part in the current study. Children were required to listen to four tones, which were paired with four different pictures and asked to learn the combinations. The children were then assessed for their ability to identify the previously learned tones, when they were presented as single tones and when they were embedded in chords and discords. No significant group differences were found. However, after subdividing the clinical group according to their diagnosis of autism or Asperger's syndrome, the results indicated a slightly superior disembedding ability in participants with Asperger's syndrome. The findings are discussed in terms of the weak central coherence concept.     

Amputees by choice: body integrity identity disorder and the ethics of amputation

ABSTRACT Should surgeons be permitted to amputate healthy limbs if patients request such operations? We argue that if such patients are experiencing significant distress as a consequence of the rare psychological disorder named Body Integrity Identity Disorder (BIID), such operations might be permissible. We examine rival accounts of the origins of the desire for healthy limb amputations and argue that none are as plausible as the BIID hypothesis. We then turn to the moral arguments against such operations, and argue that on the evidence available, none is compelling. BIID sufferers meet reasonable standards for rationality and autonomy: so as long as no other effective treatment for their disorder is available, surgeons ought to be allowed to accede to their requests.     

Evaluating three criteria for establishing cue-search hierarchies in inferential judgment

The authors identify and provide an integration of 3 criteria for establishing cue-search hierarchies in inferential judgment. Cues can be ranked by information value according to expected information gain (Bayesian criterion), cue-outcome correlation (correlational criterion), or ecological validity (accuracy criterion). All criteria significantly predicted information acquisition behavior; however, in 3 experiments, the most successful predictor was the correlational criterion (followed by the Bayesian). Although participants showed sensitivity to task constraints, searching for less information when it was more expensive (Experiment 1) and when under time constraints (Experiment 2), concomitant changes in the relative frequency of acquisition of cues with different information values were not observed. A rational analysis illustrates why such changes in the frequency of acquisition would be beneficial, and reasons for the failure to observe such behavior are discussed.     

Perceptual and lexical components of auditory repetition priming in young and older adults

In the present study, we examined whether age modulates the processing of lexical and perceptual information in auditory implicit and explicit memory tests. Young and older adults performed a surface encoding task on spoken and printed words and then either identified degraded words or made explicit recognition judgments. The implicit test of perceptual identification yielded no evidence of age-related declines in the processing of either lexical information or coarse perceptual details (modality of presentation). The same test, however, produced marked age-related declines in the processing of fine-grained perceptual details (voice) when subjects were not familiarized with the talkers' voices prior to the encoding task. Marked age differences were also observed in recognition memory. These findings suggest that although aging preserves the encoding and incidental retrieval of lexical and coarse perceptual information, it affects the encoding of fine-grained perceptual information and deliberate retrieval processes.