Illusory correlation as accentuation of actual intercategory difference: Evidence for the effect with minimal stimulus information

Distinctiveness-based illusory correlation effects (ICEs) have been implicated in the formation of negative stereotypes of minorities. In standard experiments subjects are presented with information about a large and small group in which the ratio of desirable to undesirable members is the same. These conditions normally lead to a negative representation of the smaller group. Explanations of this effect suggest it is a product of (a) over-representing highly distinctive stimuli, (b) sampling from memory, or (c) regression to the mean following information loss. The present research investigated the possibility that the ICE would occur even where no stimulus information linking behaviours to groups was presented—an outcome inconsistent with the first two explanations. Two experiments (Ns = 83, 112) produced ICEs in the absence of this standard stimulus information in a range of conditions. Results in these and previous studies are shown to be consistent with an explanation in terms of the principle of meta-contrast derived from self-categorization theory.     

Contrast and accentuation effects in category learning

This study examines the accentuation of perceived intercategory differences. In Experiment 1, 2 sets of trait adjectives were presented--a neutral set and a set of either favorable traits or unfavorable traits. Ss estimated the mean favorability of each set. The mean favorability of the neutral set was then increased or decreased by adding new traits. As predicted, the estimated mean favorability of the neutral set changed more when the set became more distinct from a contextual set than when it became more similar. In Experiment 2, estimated category means were displaced away from each other (contrast effect), and they moved even farther apart when new information increased the variability of trait favorability (accentuation effect). This change was illusory because the actual category means remained constant. Experiment 3, in which trait adjectives described members of 2 novel groups, replicated Experiment 2. The relevance of contrast and accentuation effects to the development and maintenance of differentiated intergroup perceptions is discussed.     

The minimal group paradigm: Categorization into two versus three groups

The minimal group paradigm (Tajfel, Billig, Bundy and Flament, 1971) has been influential in the study of intergroup relations. Thus far, most minimal group experiments have divided the subjects either into two groups, or have categorized them on two separate dichotomous dimensions in cross-categorization experiments. This study examines the minimal group paradigm using three distinct and independent groups. Comparison of the results with three minimal groups with those of a baseline two-group experiment shows that with a three-group structure there is no significant ingroup bias. It is suggested that the two-group minimal group experiment shows ingroup bias because subjects access a dichotomous categorization, and that this dichotomous categorization primes a competitive orientation. A two-group context may be particularly efective in evoking an ‘us versus them’ contrast. Self-categorization as a group member is more likely to occur in the presence of two groups whereas three minimal groups renders an ‘us–them’ contrastive orientation less salient. The absence of intergroup discrimination found in the present minimal group study may be limited to the behaviour of minimal or artificially created groups. In the real world of intergroup relations discrimination towards multiple outgroups is a well-known phenomenon. While this study should be regarded as only preliminary research, further elaboration and specification of the conditions under which multiple group contexts may hinder intergroup discrimination is required.     

The effects of mortality salience on intergroup bias between minimal groups

We tested the hypothesis, derived from terror management theory, that mortality salience would increase intergroup bias between minimal groups. After assignment to groups, participants wrote about death or a neutral topic, and rated the personality characteristics of the ingroup and outgroup. Results supported the hypothesis.     

知觉经验与知觉内容

知觉(perception)是指我们通过视觉、听觉、触觉、嗅觉、味觉等感觉器官而获得的对事物以及外部世界的意识感知.知觉经验(perceptual experience)的一个显著的特点是它具有某种现象特征,即知觉者会体验到一种"那究竟像什么(what it is like)"的感觉.例如,一个人会从红色视觉经验中体验到"红色究竟像什么"的意识感受性(qualia).知觉内容(perceptual content)粗略地讲是指通过知觉经验向知觉者所传递的信息.关于知觉问题在哲学上的重要性,我们可以从以下几点来看:在形而上学方面,知觉是我们了解外部物理世界究竟存在什么的主要手段;在认识论方面,研究知觉是研究我们如何达到关于外部物理世界的知识的主要手段;在语言哲学方面,知觉内容是我们的心灵与外部物理世界的关联及互动在语言实践上的体现;在心灵哲学方面,知觉经验中的现象特征与意识及意向性之间存在着深层的内在联系.     

Importance of "accentuation" for diagnostics in practical medicine

The report is about a study made in the USSR of 840 people (sick persons, female students, workers, intellectuals). All were given questionnaires acc. to H. Schmieschek in a Russian version, and the author (V. N. Belyayev) lists the results in tables and analyzes them. Reference is made to various aspects which are of importance for practical medicine and relate to a diagnosis of "accentuation" acc. to K. Leonhard.     

Perceptual grouping in audition

The present experiments evaluated the effect of relative frequency as a determinant of the figure-ground organization of sequences of auditory tones. Observers counted sequences of 20 ms tones that were presented at the same frequency or that alternated between two different frequencies. The alternating tones differed in frequency by one whole tone, seven tones, or nineteen tones. Counting accuracy increased with increases in the silent interval between the tones. When the alternating tones differed by seven or nineteen tones, counting was disrupted at rates of presentation of eight tones per second or slower. In contrast to this decrement in the counting of tones that alternated by over an octave, very little decrement was observed when the tones alternated by just one whole tone. The best subjects counted these alternating tones more accurately than the tones presented at the same frequency. The poorest subjects showed a small decrement even when the tones alternated by just one whole tone. The results were discussed in terms of determinants of figure-ground organization in auditory information processing.     

Perceptual learning in speech

This study demonstrates that listeners use lexical knowledge in perceptual learning of speech sounds. Dutch listeners first made lexical decisions on Dutch words and nonwords. The final fricative of 20 critical words had been replaced by an ambiguous sound, between [f] and [s]. One group of listeners heard ambiguous [f]-final words (e.g., [WItlo?], from witlof, chicory) and unambiguous [s]-final words (e.g., naaldbos, pine forest). Another group heard the reverse (e.g., ambiguous [na:ldbo?], unambiguous witlof). Listeners who had heard [?] in [f]-final words were subsequently more likely to categorize ambiguous sounds on an [f]-[s] continuum as [f] than those who heard [?] in [s]-final words. Control conditions ruled out alternative explanations based on selective adaptation and contrast. Lexical information can thus be used to train categorization of speech. This use of lexical information differs from the on-line lexical feedback embodied in interactive models of speech perception. In contrast to on-line feedback, lexical feedback for learning is of benefit to spoken word recognition (e.g., in adapting to a newly encountered dialect).     

Perceptual asymmetries in audition

Visual feature extraction has been investigated using search experiments. Targets that contain a feature not present in the distractors are easier to detect than if they do not, leading to search asymmetries. If sounds are decomposed into features in the auditory system, there might be asymmetries in analogous tasks. Six experiments investigating this are described. Strong asymmetries were identified, with frequency-modulated targets easier to detect among pure-tone distractors than vice versa and longer sounds easier to select from short distractors than the reverse. It is demonstrated that this asymmetry is not a result of peripheral limitations. In contrast, no asymmetries were observed between high- and low-frequency tones or between short 3-tone sequences differing only in their temporal structure. The results are discussed with reference to models of perceptual grouping and attention, the applicability of analogies between vision and audition, and possible physiological correlates. The paradigm provides a new way in which to investigate auditory feature extraction.     

Perceptual functions in prosopagnosia

Some patients with prosopagnosia may have an apperceptive basis to their recognition defect. Perceptual abnormalities have been reported in single cases or small series, but the causal link of such deficits to prosopagnosia is unclear. Our goal was to identify candidate perceptual processes that might contribute to prosopagnosia, by subjecting several prosopagnosic patients to a battery of functions that may be necessary for accurate facial perception. We tested seven prosopagnosic patients. Three had unilateral right occipitotemporal lesions, two had bilateral posterior occipitotemporal lesions, and one had right anterior-to-occipital temporal damage along with a small left temporal lesion. These lesions all included the fusiform face area, in contrast to one patient with bilateral anterior temporal lesions. Most patients had impaired performance on face-matching tests and difficulty with subcategory judgments for non-face objects. The most consistent deficits in patients with lesions involving the fusiform face area were impaired perception of spatial relations in dot patterns and reduced contrast sensitivity in the 4 to 8 cycles deg(-1) range. Patients with bilateral lesions were impaired in saturation discrimination. Luminance discrimination was normal in all but two patients, and spatial resolution was uniformly spared. Curvature and line-orientation discrimination were impaired in only one patient, who also had the most difficulty with more basic-level object recognition. We conclude that deficits in luminance, spatial resolution, curvature, line orientation, and contrast at low spatial frequencies are unlikely to contribute to apperceptive prosopagnosia. More relevant may be contrast sensitivity at higher spatial frequencies and the analysis of object spatial structure. Deficits in these functions may impair perception of subtle variations in object shape, and may be one mechanism by which the recognition defect in prosopagnosia can extend to other classes of object subcategorization.