Uncovering the root cause of ethnic difference in ability testing:differential test functioning, test familiarity and trait optimism as explanations of ethnic group differences

The present research represents a coherent approach to understanding the root causes of ethnic group differences in ability test performance. Two studies were conducted, each of which was designed to address a key knowledge gap in the ethnic bias literature. In Study 1, both the LR Method of Differential Item Functioning (DIF) detection and Mixture Latent Variable Modelling were used to investigate the degree to which Differential Test Functioning (DTF) could explain ethnic group test performance differences in a large, previously unpublished dataset. Though mean test score differences were observed between a number of ethnic groups, neither technique was able to identify ethnic DTF. This calls into question the practical application of DTF to understanding these group differences. Study 2 investigated whether a number of non-cognitive factors might explain ethnic group test performance differences on a variety of ability tests. Two factors – test familiarity and trait optimism – were able to explain a large proportion of ethnic group test score differences. Furthermore, test familiarity was found to mediate the relationship between socio-economic factors – particularly participant educational level and familial social status – and test performance, suggesting that test familiarity develops over time through the mechanism of exposure to ability testing in other contexts. These findings represent a substantial contribution to the field’s understanding of two key issues surrounding ethnic test performance differences. The author calls for a new line of research into these performance facilitating and debilitating factors, before recommendations are offered for practitioners to ensure fairer deployment of ability testing in high-stakes selection processes.

Childhood ethnic differences in ametropia and ocular biometry:the Aston Eye Study

Purpose: To describe the methodology, sampling strategy and preliminary results for the Aston Eye Study (AES), a cross-sectional study to determine the prevalence of refractive error and its associated ocular biometry in a large multi-racial sample of school children from the metropolitan area of Birmingham, England. Methods: A target sample of 1700 children aged 6–7 years and 1200 aged 12–13 years is being selected from Birmingham schools selected randomly with stratification by area deprivation index (a measure of socio-economic status). Schools with pupils predominantly (>70%) from a single race are excluded. Sample size calculations account for the likely participation rate and the clustering of individuals within schools. Procedures involve standardised protocols to allow for comparison with international population-based data. Visual acuity, non-contact ocular biometry (axial length, corneal radius of curvature and anterior chamber depth) and cycloplegic autorefraction are measured in both eyes. Distance and near oculomotor balance, height and weight are also assessed. Questionnaires for parents and older children will allow the influence of environmental factors on refractive error to be examined. Results: Recruitment and data collection are ongoing (currently N = 655). Preliminary cross-sectional data on 213 South Asian, 44 black African Caribbean and 70 white European children aged 6–7 years and 114 South Asian, 40 black African Caribbean and 115 white European children aged 12–13 years found myopia prevalence of 9.4% and 29.4% for the two age groups respectively. A more negative mean spherical equivalent refraction (SER) was observed in older children (-0.21 D vs +0.87 D). Ethnic differences in myopia prevalence are emerging with South Asian children having higher levels than white European children 36.8% vs 18.6% (for the older children). Axial length, corneal radius of curvature and anterior chamber depth were normally distributed, while SER was leptokurtic (p < 0.001) with a slight negative skew. Conclusions: The AES will allow ethnic differences in the ocular characteristics of children from a large metropolitan area of the UK to be examined. The findings to date indicate the emergence of higher levels of myopia by early adolescence in second and third generation British South Asians, compared to white European children. The continuation of the AES will allow the early determinants of these ethnic differences to be studied.

Within-country ethnic differences and product positioning:a comparison of the perceptions of two British sub-cultures

While cross-cultural consumer behaviour and its impact on marketing strategies has received considerable interest within the marketing literature, differences between ethnic groups within countries have received significantly less attention. This study examines the effect of within-country ethnic differences on brand positioning, using the UK automobile industry as a context. Both qualitative and quantitative research is used to identify the perceptions of two sub-cultural groups: British of Indian extraction, and Caucasian British. It was found that these two groups display appreciably different values, and also place different levels of importance on different product attributes when evaluating brands. Furthermore, the two groups exhibited different perceptions of the same set of brands. The results suggest that, to position brands effectively, marketers should take account of cultural diversity within countries as well as between them.

Cascaded Bayesian processes: an account of bias in orientation perception

Following adaptation to an oriented (1-d) signal in central vision, the orientation of subsequently viewed test signals may appear repelled away from or attracted towards the adapting orientation. Small angular differences between the adaptor and test yield 'repulsive' shifts, while large angular differences yield 'attractive' shifts. In peripheral vision, however, both small and large angular differences yield repulsive shifts. To account for these tilt after-effects (TAEs), a cascaded model of orientation estimation that is optimized using hierarchical Bayesian methods is proposed. The model accounts for orientation bias through adaptation-induced losses in information that arise because of signal uncertainties and neural constraints placed upon the propagation of visual information. Repulsive (direct) TAEs arise at early stages of visual processing from adaptation of orientation-selective units with peak sensitivity at the orientation of the adaptor (theta). Attractive (indirect) TAEs result from adaptation of second-stage units with peak sensitivity at theta and theta+90 degrees , which arise from an efficient stage of linear compression that pools across the responses of the first-stage orientation-selective units. A spatial orientation vector is estimated from the transformed oriented unit responses. The change from attractive to repulsive TAEs in peripheral vision can be explained by the differing harmonic biases resulting from constraints on signal power (in central vision) versus signal uncertainties in orientation (in peripheral vision). The proposed model is consistent with recent work by computational neuroscientists in supposing that visual bias reflects the adjustment of a rational system in the light of uncertain signals and system constraints.

Ethnic diversity as a multilevel construct:the combined effects of dissimilarity, group diversity, and societal status on learning performance in work groups

The authors present a model of the multilevel effects of diversity on individual learning performance in work groups. For ethnically diverse work groups, the model predicts that group diversity elicits either positive or negative effects on individual learning performance, depending on whether a focal individual’s ethnic dissimilarity from other group members is high or low. By further considering the societal status of an individual’s ethnic origin within society (Anglo versus non-Anglo for our U.K. context), the authors hypothesize that the model’s predictions hold more strongly for non-Anglo group members than for Anglo group members. We test this model with data from 412 individuals working on a 24-week business simulation in 87 four- to seven-person groups with varying degrees of ethnic diversity. Two of the three hypotheses derived from the model received full support and one hypothesis received partial support. Implications for theory development, methods, and practice in applied group diversity research are discussed.

A new randomization assay reveals Unexpected elements of sequence bias in model 'randomized' gene libraries:Implications for biopanning

Although techniques such as biopanning rely heavily upon the screening of randomized gene libraries, there is surprisingly little information available on the construction of those libraries. In general, it is based on the cloning of 'randomized' synthetic oligonucleotides, in which given position(s) contain an equal mixture of all four bases. Yet, many supposedly 'randomized' libraries contain significant elements of bias and/or omission. Here, we report the development and validation of a new, PCR-based assay that enables rapid examination of library composition both prior to and after cloning. By using our assay to analyse model libraries, we demonstrate that the cloning of a given distribution of sequences does not necessarily result in a similarly composed library of clones. Thus, while bias in randomized synthetic oligonucleotide mixtures can be virtually eliminated by using unequal ratios of the four phosphoramidites, the use of such mixtures does not ensure retrieval of a truly randomized library. We propose that in the absence of a technique to control cloning frequencies, the ability to analyse the composition of libraries after cloning will enhance significantly the quality of information derived from those libraries. (C) 2000 Published by Elsevier Science B.V. All rights reserved.

Optic flow in human vision: MEG reveals a foveo-fugal bias in V1, specialization for spiral space in hMSTs, and global motion sensitivity in the IPS

Abstract We recorded MEG responses from 17 participants viewing random-dot patterns simulating global optic flow components (expansion, contraction, rotation, deformation, and translation) and a random motion control condition. Theta-band (3–7 Hz), MEG signal power was greater for expansion than the other optic flow components in a region concentrated along the calcarine sulcus, indicating an ecologically valid, foveo-fugal bias for unidirectional motion sensors in V1. When the responses to the optic flow components were combined, a decrease in MEG beta-band (17–23 Hz) power was found in regions extending beyond the calcarine sulcus to the posterior parietal lobe (inferior to IPS), indicating the importance of structured motion in this region. However, only one cortical area, within or near the V5/hMT+ complex, responded to all three spiral-space components (expansion, contraction, and rotation) and showed no selectivity for global translation or deformation: we term this area hMSTs. This is the first demonstration of an exclusive region for spiral space in the human brain and suggests a functional role better suited to preliminary analysis of ego-motion than surface pose, which would involve deformation. We also observed that the rotation condition activated the cerebellum, suggesting its involvement in visually mediated control of postural adjustment.

Morphology in autism spectrum disorders:local processing bias and language

We conducted a detailed study of a case of linguistic talent in the context of autism spectrum disorder, specifically Asperger syndrome. I.A. displays language strengths at the level of morphology and syntax. Yet, despite this grammar advantage, processing of figurative language and inferencing based on context presents a problem for him. The morphology advantage for I.A. is consistent with the weak central coherence (WCC) account of autism. From this account, the presence of a local processing bias is evident in the ways in which autistic individuals solve common problems, such as assessing similarities between objects and finding common patterns, and may therefore provide an advantage in some cognitive tasks compared to typical individuals. We extend the WCC account to language and provide evidence for a connection between the local processing bias and the acquisition of morphology and grammar.

Ethnic conflict and war crimes in the Balkans:the narratives of denial in post-conflict Serbia

In the years following the fall of Slobodan Milo evic, Serbian social, cultural and political responses to the wars of the 1990s have fallen under intense international scrutiny. But is this scrutiny justfied, and how can these responses be better understood? Jelena Obradovic engages with ideas about post-conflict societies, memory, cultural trauma, and national myths of victimhood and justified war to shed light upon Serbian denial and justification of war crimes - for example, Serbia's reluctant cooperation with the International Criminal Tribunal for the former Yugoslavia (ICTY). Rather than treating denial as a failure to come to terms with the past or as resurgent nationalism, Obradovic argues that the justification of atrocities are often the result of a societal need to understand and incorporate violent events within culturally acceptable boundaries.

Ethnic groups as market segments: implications of the demand structure

Ethnic market potential in Britain has not yet been thoroughly researched. Important recent trends have focused mainly on the affective and emotional aspects of ethnicity, and included deliberations on the emergence of a revitalised neo-ethnic consciousness; its identification; politicisation, and the impact on it; of a rising third-world consciousness. This investigation attempts to take cognizance of the consuner demand of the ethnic Asian and West Indian groups, as specific market segments. It discusses the rationale for ethnic segmentation on the underlying premise, that the starting point for all product marketing is a response to perceived market opportunities. On the basis of this approach, the UK laundry detergent and automobile markets were investigated; as being representative of product categories constitutirg extremes along the purchase-search-time continuun in consuner decision-making. Ethnic groups were further analysed for their retail patronage patterns; media usage, and the differential effectiveness of alternative advertisirg strategies. The basic technique of marketing research namely the sample survey, was used with the aim of applying scientific techniques in obtaining information on ethnic groups. The integrated marketirg framework utilised allowed, moreover, for the collection of market research data on the specific issues of ethnic product penetration dealing with retailing, advertising and product promotion. The evidence highlights the fact that the cultural orientations of ethnic groups are instrunental in providing for differential demand structures. It points to the answer that ethnicity is an anchor not only for a deeper sense of identity; but also serves as a focus for the economic interests of ethnic groups. On this basis it is argued here, that since cultural levelling would eventually produce stagnation; current marketing strategies should utilise ethnic diversity as an econanic artifact; which; per se is necessary for profitability and growth; especially in innovative product design and development.

A political economy of the ethnic chinese catering industry

The present political climate in which the ideals of entrepreneurship and self-help are strongly encouraged has drawn attention to those ethnic minorities noted for their entrepreneurial activity. Since the Chinese appear to be an exemplary case in point, this thesis focusses upon the historical material conditions which have led to the formation of a Chinese 'business* community in Britain, both past and present As such, it rejects the theories of cultural determinism which characterise most studies of the Chinese. For rather than representing the endurance of cultural norms, the existence of the contemporary Chinese 'niche' of ethnically exclusive firms in the catering industry is due to the conjunction of a number of historical processes. The first is the imperialist expansion into China of Britain's capitalist empire during the nineteenth century which established a relationship of dependency upon the interests of British capital by colonial Chinese labour. The second is the post war development of the catering industry and its demand for cheap labour as administered by the British state together with the contemporaneous development of the agricultural economy of colonial Hong Kong. Far from representing a source of material benefit to all, the ethnic Chinese 'niche' in catering is highly exploitative and merely underlines the racial oppression of Chinese in Britain. Attempts to promote business interests within the ethnic community therefore serve merely to entrench the structures of oppression.