Endogenous testosterone concentration, mental rotation, and size of the corpus callosum in a sample of young Hungarian women

In the present study brain laterality, hemispheric communication, and mental rotation performance were examined. A sample of 33 women were tested for a possible linear relationship of testosterone level and mental rotation with structural background of the brain. Subjects with a smaller splenial area of corpus callosum tended to have lower levels of testosterone (r =.37, p<.05). However, there were no significant differences in mean scores of mental rotation of object and hand between groups with high and low levels of testosterone. There was a significant difference in relative size of the 6th area (slice) of the corpus callosum between groups with good and poor scores on mental rotation of an object and also in relative size of the 4th and 5th slices of the corpus callosum between groups on mental rotation of the hand. The good and poor scorers' show different relations with the measures of the corpus. The mental rotation of hand was associated with the parietal areas of the corpus callosum, while the mental rotation of object was associated only with the occipital area. These observations suggest that higher testosterone levels may be associated with a larger splenial area, which represents an important connection between the parieto-occipitocortical areas involved in activation of mental images. Further srudy is encouraged.     

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.     

Attentional and behavioural responses of spider fearfuls to virtual spiders

This study employed an immersed virtual environment (IVE) in the Nijmegen RIVERlab to study spider fearfuls’ attentional and motor reactions to virtual spiders. The participants were exposed to virtual spiders while completing an unrelated task, walking freely through a virtual museum. Compared to non-fearful controls, spider fearfuls showed an increase in state anxiety, they spent more time looking at spiders, and they exhibited spontaneous behavioural avoidance of spiders and visually similar objects. The results extend, and to some degree contradict, those of earlier studies with static pictures, and they speak to the usefulness of state-of-the-art IVEs in fundamental anxiety research.