Exploring Asian American racial identity

In this study the authors used cluster analysis to create racial identity profiles for a sample of Asian Americans using the People of Color Racial Identity Attitudes Scale (PCRIAS). A four-cluster solution was chosen: each cluster corresponded to one PCRIAS subscale and was named accordingly. Scores on the Asian American Racism-Related Stress Inventory and the Color-Blind Racial Attitudes Scale were compared across clusters. As expected, the Dissonance and Immersion clusters were characterized by relatively high racism-related stress and low levels of color-blind attitudes; the Conformity cluster showed roughly the opposite pattern. Surprisingly, the Internalization cluster showed a pattern similar to that for Conformity and thus may reflect "pseudoindependence" as discussed by Helms.     

Do humans and baboons use the same information when categorizing human and baboon faces?

What information is used for sorting pictures of complex stimuli into categories? We applied a reverse correlation method to reveal the visual features mediating categorization in humans and baboons. Two baboons and 6 humans were trained to sort, by species, pictures of human and baboon faces on which random visual noise was superimposed. On ambiguous probe trials, a human-baboon morph was presented, eliciting "human" responses on some trials and "baboon" responses on others. The difference between the noise patterns that induced the two responses made explicit the information mediating the classification. Unlike the humans, the baboons based their categorization on information that closely matched that used by a theoretical observer responding solely on the basis of the pixel similarities between the probe and training images. We show that the classification-image technique and principal components analysis provide a method to make explicit the differences in the information mediating categorization in humans and animals.     

Growing older does not always mean moving slower: examining aging and the saccadic motor system

Although humans typically move more slowly as they age, one exception may be the saccadic motor system. To fully determine whether the execution of saccades is affected by age, the authors examined detailed kinematics of vertical and horizontal saccades across a range of saccadic amplitudes (4 degrees, 8 degrees, and 12 degrees). Ten younger and 20 older adults participated in each experiment. Whereas in the 1st experiment, the authors assessed volitionally generated saccades, in the 2nd experiment, they evaluated reflexively generated saccades. The results of those experiments showed that the saccadic motor system is relatively impervious to the effects of aging; in fact, the differences between vertical and horizontal saccades were more evident than were differences between saccades produced by younger and older adults. The authors discuss possible reasons for that relative resistance to aging.     

Symbolic and nonsymbolic number comparison in children with and without dyscalculia

Developmental dyscalculia (DD) is a pervasive difficulty affecting number processing and arithmetic. It is encountered in around 6% of school-aged children. While previous studies have mainly focused on general cognitive functions, the present paper aims to further investigate the hypothesis of a specific numerical deficit in dyscalculia. The performance of 10- and 11-year-old children with DD characterised by a weakness in arithmetic facts retrieval and age-matched control children was compared on various number comparison tasks. Participants were asked to compare a quantity presented in either a symbolic (Arabic numerals, number words, canonical dots patterns) or a nonsymbolic format (noncanonical dots patterns, and random sticks patterns) to the reference quantity 5. DD children showed a greater numerical distance effect than control children, irrespective of the number format. This favours a deficit in the specialised cognitive system underlying the processing of number magnitude in children with DD. Results are discussed in terms of access and representation deficit hypotheses.     

Mimicking disliked others: Effects of a priori liking on the mimicry‐liking link

The sharing of bodily states elicits in mimicker and mimickee corresponding conceptualisations, which facilitates liking. There are many studies showing the relatedness of mimicry and liking. However, the mimicry‐liking link has not been investigated under conditions in which the mimickee is liked or disliked a priori. In two studies, we examined moderating effects of a priori liking on the mimicry‐liking link. Liking was measured via self‐report measures (Studies 1 and 2) and behavioural measures using a virtual environment technology (Study 2). Results showed that when participants intentionally mimicked a disliked person, liking for that person was not improved, whereas when participants mimicked a liked person, liking for that person increased. These effects were shown to be mediated by affiliation. These studies not only provided further evidence of a link between mimicry and liking, but also demonstrated that this relationship is moderated by a priori liking. Copyright © 2009 John Wiley & Sons, Ltd.     

Prejudice in the police: On the processes underlying the effects of selection and group socialisation

The principal aim of this study is to determine why police officers are generally found to be more prejudiced towards disadvantaged groups than are the standard population. Two independent processes were expected to account for this effect: Selection and group socialisation. Using a cross‐sectional design (N = 170), firstly, we compared, newly recruited police officers with a control population (selection effect), and secondly, police officers with 1 year of training with the newly recruited ones (group socialisation effect). Results reveal a significant effect of both selection and group socialisation, the two being underlined by distinct processes; right‐wing authoritarianism (RWA) in the case of the former and internalisation of a prejudice norm in the case of the latter. Finally, the results show that group identification moderates the change in internalisation of the prejudice norm. Copyright © 2009 John Wiley & Sons, Ltd.     

Sign determination of the 57 Fe electric-field gradient in Al-based crystals and icosahedral quasicrystals

Abstract

The icosahedral quasicrystals i-AIMn, isomorphically substituted by 28 at.% Fe or by a mixture of (CrFe) atoms, have been studied for the first time by in-field Mössbauer spectroscopy in order to determine the sign and asymmetry parameter of the dominant electric-field gradient (EFG) term. In addition, the orthorhombic o-Al(MnFe) and cubic α- and hexagonal β-Al(MnFe)Si crystalline phases have been studied. We show that the previous Mössbauer results are inadequate for determining whether there are two sites in the quasicrystalline structure in the ratio of the golden number. Our results for i-Al(MnFe) show that the dominant EFG is negative, with an asymmetry parameter of about 0·6. For i-Al(CrFe), essentially no deviations are found from the model of Czjzek or the Gaussian isotropic model. One crystalline phase, the hexagonal β phase, is found to have a very similar quadrupole effect to that found in i-Al(MnFe). In addition it is found that this phase undergoes a change which is at least partly of magnetic origin.     

The Role of Concurrent Feedback in Learning to Walk Through Sliding Doors

Concurrent feedback is defined as information about performance given to participants during the execution of an action. This article investigates whether concurrent feedback is beneficial or detrimental to the learning of an ecologically relevant task. Eighteen participants were asked to walk through a virtual corridor and they practiced over 1110 trials to adjust their walking speed so as to pass through sliding doors that opened and closed at a frequency of 1 Hz. Concurrent feedback informed them about the possible need to accelerate or decelerate. Performance of participants who received concurrent feedback on 66% of the practice trials (on average) did not differ significantly from performance of participants who did not receive concurrent feedback. Furthermore, participants of both of these groups significantly outperformed participants who received concurrent feedback on all practice trials. These results are discussed in relation to the perceptual-motor mechanisms that underlie the control of the action. Also discussed are implications for future research, including the use of self-controlled feedback and the use of multisensory training programs.     

Index for Volume 23

In this study, changes in movement coordination caused by fatigue that developed during repetitive lifting were examined. Five men performed 6 times a 5-min bout of lifting an 8-kg barbell at 15 lifts/min, using two lifting techniques; one minimized trunk rotation (squat lift), and the other minimized rotation in the knee joint (stoop lift). Kinematics and dynamics were studied by means of movement analysis and inverse dynamics, using a two-dimensional linked segment model. Within-subject variation over repetitive lifts of the time course of joint angles was smaller than between-subjects variation on the first analyzed lift. Relative timing between joint rotations did not change significantly across repetitive lifts, except between knee and hip in the squat lift. No change of the lumbosacral torque over repetitive lifts was found. The adaptability of the neural control appeared to be sufficient to accommodate the strong changes of the input-output characteristics of the muscles caused by fatigue so that an essentially constant performance of the movement act was maintained.