Computational approaches to the development of perceptual expertise

Dog experts, ornithologists, radiologists and other specialists are noted for their remarkable abilities at categorizing, identifying and recognizing objects within their domain of expertise. A complete understanding of the development of perceptual expertise requires a combination of thorough empirical research and carefully articulated computational theories that formalize specific hypotheses about the acquisition of expertise. A comprehensive computational theory of the development of perceptual expertise remains elusive, but we can look to existing computational models from the object-recognition, perceptual-categorization, automaticity and related literatures for possible starting points. Arguably, hypotheses about the development of perceptual expertise should first be explored within the context of existing computational models of visual object understanding before considering the creation of highly modularized adaptations for particular domains of perceptual expertise.     

The US-preexposure effect in lithium-induced flavor-aversion conditioning is a consequence of blocking by injection cues

In 2 experiments, rats received flavor-aversion conditioning in which the unconditioned stimulus (US) was an orally consumed solution of lithium chloride (LiCl). The resulting aversion was not attenuated by giving preexposure to injections of LiCl, although such preexposure did attenuate aversions established using injected LiCl as the US (Experiment 1). This outcome suggests that blocking by injection-related cues is responsible for the US-preexposure effect observed in this situation. Experiment 2 confirmed this interpretation by showing that presenting such cues (by giving an injection of saline) at the time that the LiCl was drunk resulted in an attenuation of conditioning in animals preexposed to injections of LiCl. The US-preexposure effect obtained in these experiments can be explained solely in terms of blocking by injection cues, although other mechanisms may contribute to the effect seen in other flavor-aversion paradigms.     

How are social identities linked to self-conception and intergroup orientation? The moderating effect of implicit theories

Social identity approaches assume that social identification affects both self-conception and intergroup orientation. The authors contend that such social identification effects are accentuated when people hold a fixed view of human character and attribute immutable dispositions to social groups. To these individuals, social identities are immutable, concrete entities capable of guiding self-conception and intergroup orientation. Social identification effects are attenuated when people hold a malleable view of human character and thus do not view social identities as fixed, concrete entities. The authors tested and found support for this contention in three studies that were conducted in the context of the Hong Kong 1997 political transition, and discussed the findings in terms of their implications for self-conceptions and the meaning of social identification.     

Pigeons use item-specific and category-level information in the identification and categorization of human faces

Three experiments examined the pigeon's ability to adapt to the specific tasks of identification and categorization of complex visual stimuli by attending to information at different levels of abstraction. In Experiment 1, pigeons were successively trained to discriminate first between pairs of human faces from the same sex and then between male and female faces. A final test revealed that the associations formed in the first training phase did not survive categorization training, indicating that the pigeons used item-specific information to discriminate faces of the same sex, but shifted their attention to category-level information for discriminating between the male and female categories. Two further experiments disproved alternative explanations. The results support the feature-learning account of open-ended categorization in animals.     

Bouncing Back from Setbacks: On the Mediating Role of Team Resilience in the Relationship Between Transformational Leadership and Team Effectiveness

The purpose of this study was to clarify the role of team resilience on different facets of effectiveness (team viability and quality of the group experience). Moreover, given the importance of team resilience for the organizational context, it was also our aim to contribute to the study of the conditions that promote team resilience, analyzing the role of transformational leadership. Finally, we examined whether the relationship between transformational leadership and team resilience stimulates positive team outcomes. Ninety teams (445 employees from 40 companies) were surveyed and path analysis was used in the test of the hypotheses. The results showed a positive direct effect of team resilience on both team viability and the quality of the group experience. Moreover, a positive relationship was also identified between transformational leadership and team resilience. Finally, support was found for the mediated effect of team resilience on the relationship between transformational leadership and the dimensions of team effectiveness considered. The findings of this study highlight the role of team resilience as an intervening process between transformational leadership and team effectiveness. Supervisors should promote team resilience, adopting transformational leadership behaviors, in order to contribute to increase team viability and the quality of the group experience.     

Chinese children's imaginary companions: Relations with peer relationships and social competence

We investigated relationships between Chinese children's imaginary companions (ICs) and peer relationships and social competence in 160 children, aged 5–6 years old. Children and their mothers participated in the interviews regarding the details of the children's ICs, including the type of the companion and the quality of the child–IC relationship. Peer relationships were assessed using sociometric nomination and perceived popularity nomination. Teachers rated children's social competence. Here, 55 children (34.3%) were deemed to have engaged in imaginary companion play. There was no relationship between imaginary companion types and child–IC relationship qualities. Children with invisible friends received more positive nominations than children with personified objects. Children with egalitarian relationships received more positive nominations and popularity nominations, but fewer negative nominations and unpopularity nominations than children with hierarchical relationships. Compared with children with hierarchical relationships, teachers rated the children with egalitarian relationships higher in social competence. The results suggest that imaginary companion types and relationship qualities may represent different dimensions of imaginary companions, calling attentions to the different mechanisms underlying imaginary companion types and relationship qualities with respect to social functioning.     

A novel working memory task for preschoolers: sensitivity to age differences from 3-5 years

Working memory (WM) plays an important role in children’s learning and is linked to later academic and occupational success. Understanding the early development of WM can provide critical clues regarding the underlying structure of executive functions and how they change over the life span. The main objectives of the present study were to (1) investigate age differences in the development of three components of WM (retrieval, substitution, transformation) on a novel preschool WM measure and (2) explore whether findings are consistent with the hierarchical model of WM development by examining perseverative and non-perseverative WM errors. Perseverative errors were hypothesized to be more strongly associated with problems substituting and transforming a representation held in mind, whereas non-perseverative errors were hypothesized to be associated with problems maintaining a representation in mind. Participants were 64 children ranging in age from 3.0 to 5.6 years. The results provide evidence for the sensitivity of the WM task to age differences from 3 to 5 years and support for the hierarchical model of WM development.     

A lexical analysis of environmental sound categories

In this article we report on listener categorization of meaningful environmental sounds. A starting point for this study was the phenomenological taxonomy proposed by Gaver (1993b). In the first experimental study, 15 participants classified 60 environmental sounds and indicated the properties shared by the sounds in each class. In a second experimental study, 30 participants classified and described 56 sounds exclusively made by solid objects. The participants were required to concentrate on the actions causing the sounds independent of the sound source. The classifications were analyzed with a specific hierarchical cluster technique that accounted for possible cross-classifications, and the verbalizations were submitted to statistical lexical analyses. The results of the first study highlighted 4 main categories of sounds: solids, liquids, gases, and machines. The results of the second study indicated a distinction between discrete interactions (e.g., impacts) and continuous interactions (e.g., tearing) and suggested that actions and objects were not independent organizational principles. We propose a general structure of environmental sound categorization based on the sounds' temporal patterning, which has practical implications for the automatic classification of environmental sounds.