A probabilistic account of exemplar and category generation

People are capable of imagining and generating new category exemplars and categories. This ability has not been addressed by previous models of categorization, most of which focus on classifying category exemplars rather than generating them. We develop a formal account of exemplar and category generation which proposes that category knowledge is represented by probability distributions over exemplars and categories, and that new exemplars and categories are generated by sampling from these distributions. This sampling account of generation is evaluated in two pairs of behavioral experiments. In the first pair of experiments, participants were asked to generate novel exemplars of a category. In the second pair of experiments, participants were asked to generate a novel category after observing exemplars from several related categories. The results suggest that generation is influenced by both structural and distributional properties of the observed categories, and we argue that our data are better explained by the sampling account than by several alternative approaches.     

Giant African Pouched Rats as Detectors of Tuberculosis in Human Sputum: Comparison of Two Techniques for Sputum Presentation

Previous studies have shown that pouched rats can detect the presence of Mycobacterium tuberculosis, which causes tuberculosis, in human sputum samples obtained from clinical facilities. Although pouched rats evaluate sputum samples quickly, preparing the samples is relatively slow. The present study evaluated whether the rats can detect tuberculosis in microscope slides, which are routinely prepared at these facilities. Results indicate that they can do so, but their accuracy is considerably lower than that of rats exposed to pots containing sputum, as in prior studies.

     

Disrupting feedback processing interferes with rule-based but not information-integration category learning

The effect of a sequentially presented memory scanning task on rule-based and information-integration category learning was investigated. On each trial in the short feedback-processing time condition, memory scanning immediately followed categorization. On each trial in the long feedback-processing time condition, categorization was followed by a 2.5-sec delay and then memory scanning. In the control condition, no memory scanning was required. Rule-based category learning was significantly worse in the short feedback-processing time condition than in the long feedback-processing time condition or control condition, whereas information-integration category learning was equivalent across conditions. In the rule-based condition, a smaller proportion of observers learned the task in the short feedback-processing time condition, and those who learned took longer to reach the performance criterion than did those in the long feedback-processing time or control condition. No differences were observed in the information integration task. These results provide support for a multiple-systems approach to category learning and argue against the validity of single-system approaches.     

A Unified Theory of the Atonement

Abstract:  Following Aulén, three broad, and competing, models of the atonement are outlined in this article, and an argument is offered to suggest that the mediatorial model should be considered normative. The argument proceeds through discussion with N.T. Wright's adoption of the victory model as normative in his expositions of Pauline theology. It is here suggested that the victory model is inherently unsuitable as a paradigm for the soteriology of Romans, and argued that the assertion that it can explain the process of reconciliation lacks foundation. Further, there is indication as to how the occasional language of victory in the New Testament can often be incorporated naturally within a mediation framework.     

Assessment of Parenting Practices Related to Conduct Problems: Development and Validation of the Management of Children's Behavior Scale

We report on the development and initial validation of the parent-report scale, Management of Children's Behavior Scale (MCBS), designed to evaluate parenting practices related to conduct problems in children. Children (N=396, ages 2-14) referred for outpatient treatment and their parents served as participants. We evaluated the composition and consistency of the scale and provided evidence pertaining to concurrent, predictive, and incremental validity. Evidence for each type of validity was consistent with the conceptualization of the scale and the pertinence to child conduct problems. The measure also was sensitive to therapeutic changes. Parenting practices targeted in treatment (parent management training) improved as predicted over time. The results suggest the measure may be useful in evaluating parenting practices known to relate to conduct problems and often targeted for intervention in parent- and family-based treatment.     

Internal consistency reliability of the Francis Scale of Attitude toward Alcohol among adolescents in Northern Ireland

The Francis Scale of Attitude toward Alcohol was completed by 324 adolescents (M= 17.1 yr., SD=3.6) in Northern Ireland to examine reliability of the measure among this age group. These data support its internal consistency (.89) and suggest that the Francis Scale of Attitude toward Alcohol is psychometrically appropriate for use among this age group.     

The relationship between short-term memory and working memory: complex span made simple?

This experiment addresses the question of what makes a working memory measure a good predictor of higher-level abilities. Verbal and visuospatial processing episodes were interleaved with distinct verbal and visuospatial storage episodes to form four complex span tasks. Although these measures were reliable predictors of reading and mathematics ability in children, they were no more predictive of these abilities than corresponding simple span tasks involving storage alone. However, when individual differences in storage ability and processing capacity were controlled for, residual variance in complex span performance was related to academic ability in some cases. These findings indicate that complex span tasks are multiply determined, and that differences in task structure can dramatically influence the relative importance of these multiple constraints and the predictive power of a complex span measure.     

Examining task difficulty and the time course of inhibition of return: detecting perceptually degraded targets.

The ability to efficiently direct visual attention to salient features in the environment is a critical function of the visual system. The finding that people are slower to detect a target that appears at a previously cued location is thought to reflect a mechanism known as inhibition of return (IOR). Past research has shown that difficult target discriminations result in a greater amount of time needed to inhibit previously attended locations (i.e., a delayed onset of inhibition), suggesting that task difficulty plays a critical role in the allocation of attention. In this study, IOR was measured at a wide range of SOAs while participants detected either a perceptually degraded target or a standard, high luminance target. When responses were made to a perceptually degraded target, the time course of IOR was delayed by approximately 250 ms (relative to the control group), suggesting that the difficulty in detecting targets also influences the allocation of attention. The results are consistent with the notion that IOR is not simply a reflexive subcortical mechanism but rather involves top-down attentional control settings.     

Constraints on view combination: effects of self-occlusion and differences among familiar and novel views

The use of multiple familiar views of objects to facilitate recognition of novel views has been addressed in a number of behavioral studies, but the results have not been conclusive. The present study was a comprehensive examination of view combination for different types of novel views (internal or external to the studied views) and different objects (amoeboid objects and objects composed of geons; objects with and without self-occlusion across rotation). The authors found that the advantage gained from the study of 2 views was more than the generalization from each of the studied views presented alone. This facilitation occurred only for internal views but not external views. In addition, the benefits from the study of 2 views diminished when (a) the studied views did not share the same visible features and when (b) the studied views were separated by a small angular difference.