Representational masking and the attentional blink

After successful detection of a target item within a stream of rapidly displayed visual stimuli, subsequent detection of an additional target is impaired for roughly 500 ms. This impairment is known as the “attentional blink” (AB). Previous studies have found that if either the first (Tl; Raymond, Shapiro, & Arnell, 1992) or second target (T2; Giesbrecht & Di Lollo, 1998) is not followed by a mask, the AB impairment is significantly reduced. Whereas low-level perceptual factors have been found to influence the efficacy of masking in the AB (e.g., Seiffert & Di Lollo, 1997), the current experiment used a higher level (representational) manipulation, i.e., repetition blindness to reduce the efficacy of target masking in the AB. These findings contribute to the growing literature suggesting that masking plays more than a perceptual role in the AB phenomenon.     

3─6岁儿童层级类概念发展的实验研究

以３－６岁儿童为被试,以７个常见物体种类的图片为实验材料,按概念水平（基本类概念及上级类概念）以及选择图与目标图的感知相似程度（高、中、低）将实验材料分为四种类型,对３－６岁儿童层级类概念的发展过程进行了研究。结果表明：（１）３岁幼儿已能按基本类概念标准进行正确的种类匹配;对于上级类概念,３－５岁儿童的匹配能力尚较差,６岁基本达到掌握水平。（２）实验材料的感知相似程度对３－５岁儿童的上级类概念匹配操作有显著性影响,６岁儿童才摆脱了这种制约作用。     

3─6岁儿童层级类概念发展的实验研究

以３－６岁儿童为被试,以７个常见物体种类的图片为实验材料,按概念水平（基本类概念及上级类概念）以及选择图与目标图的感知相似程度（高、中、低）将实验材料分为四种类型,对３－６岁儿童层级类概念的发展过程进行了研究。结果表明：（１）３岁幼儿已能按基本类概念标准进行正确的种类匹配;对于上级类概念,３－５岁儿童的匹配能力尚较差,６岁基本达到掌握水平。（２）实验材料的感知相似程度对３－５岁儿童的上级类概念匹配操作有显著性影响,６岁儿童才摆脱了这种制约作用。     

Conceptual Hierarchies in a Flat Attractor Network: Dynamics of Learning and Computations

The structure of people's conceptual knowledge of concrete nouns has traditionally been viewed as hierarchical ( Collins & Quillian, 1969 ). For example, superordinate concepts ( vegetable ) are assumed to reside at a higher level than basic-level concepts ( carrot ). A feature-based attractor network with a single layer of semantic features developed representations of both basic-level and superordinate concepts. No hierarchical structure was built into the network. In Experiment and Simulation 1, the graded structure of categories (typicality ratings) is accounted for by the flat attractor network. Experiment and Simulation 2 show that, as with basic-level concepts, such a network predicts feature verification latencies for superordinate concepts ( vegetable ). In Experiment and Simulation 3, counterintuitive results regarding the temporal dynamics of similarity in semantic priming are explained by the model. By treating both types of concepts the same in terms of representation, learning, and computations, the model provides new insights into semantic memory.     

Towards tolerance: Representations of superordinate categories and perceived ingroup prototypicality

According to Mummendey and Wenzel (1999), group members tend to perceive their ingroup, relative to an outgroup, as more prototypical of the superordinate category encompassing both groups. Hence, they tend to regard the outgroup as deviating from the norms of the superordinate category. Factors that inhibit perception of relative ingroup prototypicality should thus promote intergroup tolerance. In two experiments, the representation of the superordinate category was manipulated. Both an undefinable prototype (Experiment 1; N=63) and a complex representation (Experiment 2; N=88) led to a decrease in relative ingroup prototypicality. Dual identification with the ingroup and the superordinate category increased relative ingroup prototypicality, which was negatively correlated with positive attitudes towards the outgroup. The findings supported Mummendey and Wenzel’s assumptions about the conditions that lead to intergroup tolerance.     

When “different” means “worse”: In-group prototypicality in changing intergroup contexts

An experiment with 213 participants provided evidence for in-group projection—the generalization of distinctive in-group attributes to a superordinate category. The frame of reference for in-group (German) judgments was manipulated by presenting either Italians or the British as an out-group. Results showed that attributes on which Germans differed from each out-group were accentuated not only in in-group judgments but also when judging Europeans. By adapting features of the superordinate category to those of the in-group, the in-group's similarity to, and the out-group's deviation from, the prototype of the superordinate category were maintained, if not emphasized. Further, higher in-group prototypicality—compared to out-group prototypicality—for the superordinate category was related to negative out-group attitudes. In-group projection was reduced when a complex representation of the superordinate category was primed.     

Category-specificity can emerge from bottom-up visual characteristics: evidence from a modular neural network

The role of bottom-up visual processes in category-specific object recognition has been largely unexplored. We examined the role of low-level visual characteristics in category specific recognition using a modular neural network comprising both unsupervised and supervised components. One hundred standardised pictures from ten different categories (five living and five nonliving, including body parts and musical instruments) were presented to a Kohonen self-organising map (SOM) which re-represents the visual stimuli by clustering them within a smaller number of dimensions. The SOM representations were then used to train an attractor network to learn the superordinate category of each item. The ease with which the model acquired the category mappings was investigated with respect to emerging category effects. We found that the superordinates could be separated by very low-level visual factors (as extracted by the SOM). The model also accounted for the well documented atypicality of body parts and musical instrument superordinates. The model has clear relevance to human object recognition since the model was quicker to learn more typical category exemplars and finally the model also accounted for more than 20% of the naming variance in a sample of 57 brain injured subjects. We conclude that purely bottom-up visual characteristics can explain some important features of category-specific phenomena.     

Superordinate identities and intergroup conflict: The ingroup projection model

This chapter summarises results from a research programme on the psychological basis of tolerance and discrimination in intergroup relations, with particular consideration of the role of superordinate identities. According to the ingroup projection model, a relevant superordinate group provides dimensions and norms for comparisons between ingroup and outgroup. Groups gain positive value or status when they are considered prototypical for the (positively valued) superordinate group. Group members tend to generalise (project) distinct ingroup characteristics onto the superordinate category, implying the relative prototypicality of their ingroup. To the extent that outgroup difference is regarded as a deviation from the ethnocentrically construed prototype it is evaluated negatively. Our research studied consequences and determinants of ingroup projection, as well as moderators of its implications. The findings contribute to a deeper understanding of the processes involved in intergroup discrimination and indicate new pathways for the reduction of prejudice, towards mutual intergroup appreciation and tolerance.