Enhanced right hemisphere activation in the mathematically precocious: A preliminary EEG investigation

A preliminary electroencephalographic (EEG) investigation was conducted to determine if the pattern of hemispheric activation in mathematically precocious youth differs from that of average math ability subjects. Alpha activity at four brain sites (frontal, temporal, parietal, and occipital lobes) over the left and right cerebral hemispheres (LH/RH) was monitored while 12- to 14-year-old, right-handed males: (a) looked at a blank slide (baseline condition), (b) judged which of two chimeric faces was "happier," and (c) determined if a word was a noun or a verb. At baseline, the LH of the precocious group was found to be more active at all four brain sites relative to that of the average ability group. During chimeric face processing, the gifted subjects exhibited a significant reduction in alpha power over the RH, primarily at the temporal lobe, while no such alpha suppression was observed in the average ability subjects. For noun/verb determinations, no significant alpha power reductions were obtained for either group. These electrophysiological data generally corroborate the behavioral findings of O'Boyle and Benbow (1990a) and support their contention that enhanced RH involvement during cognitive processing may be a correlate of mathematical precocity. Moreover, the pattern of activation observed across tasks suggests that the ability to effectively coordinate LH and RH processing resources at an early age may be linked to intellectual giftedness.     

Schizophrenia and deliberate self-harm: a systematic review of risk factors

Deliberate self-harm (DSH) is a strong predictor of suicide in schizophrenia. The aim of this review was to identify risk factors for DSH in schizophrenia. This systematic review of the international literature examined cohort and case-control studies of patients with schizophrenia or related diagnoses that reported DSH as an outcome. Studies were identified by searching electronic databases and reference lists, and by consulting international experts. Fourteen studies met the eligibility criteria. Of the 29 variables examined by two or more studies, five (past or recent suicidal ideation, previous DSH, past depressive episode, drug abuse or dependence, and higher mean number of psychiatric admissions) were associated with an increased risk of DSH, and one (unemployment) was associated with a reduced risk. Schizophrenic patients with these risk factors need careful follow-up and monitoring, with treatment of any associated comorbid depression or drug abuse. Large, prospective studies of DSH in schizophrenia are needed to further define risk factors and to build on the findings of this review.     

Representation of two geometric features of the environment in the domestic chick (<Emphasis Type="Italic">Gallus gallus</Emphasis>)

We report experiments based on a novel test in domestic chicks (Gallus gallus), designed to examine the encoding of two different geometric features of an enclosed environment: relative lengths of the walls and amplitude of the corners. Chicks were trained to search for a food reward located in one corner of a parallelogram-shaped enclosure. Between trials, chicks were passively disoriented and the enclosure was rotated, making reorientation possible only on the basis of the internal spatial structure of the enclosure. In order to reorient, chicks could rely on two sources of information: the relative lengths of the walls of the enclosure (associated to their left-right sense order) and the angles subtended by walls at corners. Chicks learned the task choosing equally often the reinforced corner and its rotational equivalent. Results of tests carried out in novel enclosures, the shapes of which were chosen ad hoc (1) to induce reorientation based only on the ratio of walls lengths plus sense (rectangular enclosure), or (2) to induce reorientation based only on corner angles (rhombus-shaped enclosure), suggested that chicks encoded both features of the environment. In a third test, in which chicks faced a conflict between these geometric features (mirror parallelogram-shaped enclosure), reorientation seemed to depend on the salience of corner angles. These results shed light on the elements of the environmental geometry which control spatial reorientation, and broaden the knowledge on the geometric representation of space in animals.     

Knowing in advance: the impact of prior event information on memory and event knowledge

We examined the influence of newly acquired information on children's memory and general representation of a personally experienced event. Thirty-five children between the ages of 5 and 7 years participated in the novel event (Visiting the Pirate). The day before participating, children were: (1) provided with new information specific to the up-coming event; (2) engaged in a discussion generally related to the event topic based on existing knowledge; or (3) discussed an unrelated topic. Advance information specific to the event led to better recall and, in particular, to better integration of the experience into a general event representation both soon after the event and at a follow-up interview 4 months later, whereas general discussion of the topic without the event specific information neither enhanced memory reports nor facilitated the integration of event information. Providing information in advance can have significant effects on memory and knowledge acquisition although many variables, including those relating to the specific content of the information, will affect this relation.     

Modality-specific effects in inhibitory mechanisms: the interaction of peripheral and central components in working memory

Working memory is a complex system assumed to encompass both storage and processing components. At the same time, several authors have suggested the existence of separate peripheral modality-specific subsystems, in particular a verbal and a visuo-spatial mechanism. In the present research, we explored the hypothesis that modality-specific mechanisms may also operate in the central processing component. Inhibitory control has traditionally been considered as a typical function of the central executive, devoted to selecting, processing, and eliminating irrelevant information. We designed verbal and visuo-spatial tasks involving similar procedures and comparable levels of inhibitory control. Results indicate that accuracy profiles are similar in the two conditions; however, the patterns of data measuring inhibitory control, i.e., percentage of intrusion errors, are opposite in the case of verbal (intrusions decreased in more complex trials) and visuo-spatial (intrusions increased in more complex trials) material. These data are consistent with theoretical models of working memory suggesting that modality-specific effects emerge even in central processes and that both material-dependent and process-dependent features must be considered in working memory tasks.     

Measures of visuospatial short-term memory: the Knox Cube Imitation Test and the Corsi Blocks Test compared

The present investigation analyzes the characteristics of two tasks that have been considered as a measure of visuospatial abilities: The Knox Cube Imitation Test and the Corsi Blocks Test. The former was originally devised by Knox (1913) to diagnose mental retardation in potential immigrants to the United States, while the latter has been specifically designed to be used in neuropsychological practice by Corsi (1972). Although both tasks have been widely used in the past, there is little empirical research investigating the characteristics of these tasks from a theoretical point of view. In order to do so, we carried out two parallel experiments in which both tasks were presented in a baseline condition as well as in association with three different concurrent tasks (i.e., articulatory suppression, spatial tapping, and random generation) supposed to tap the various components of working memory. Results showed that neither of the tasks can be considered as a pure measure of visuospatial processing and that, at the same time, it is necessary to reconsider the architecture of working memory in order to suggest a more integrated functioning of the system.     

Spatial biases in peripersonal space in sighted and blind individuals revealed by a haptic line bisection paradigm

Our representation of peripersonal space does not always accurately reflect the physical world. An example of this is pseudoneglect, a phenomenon in which neurologically normal individuals bisect to the left of the veridical midpoint, reflecting an overrepresentation of the left portion of space compared with the right one. Consistent biases have also been observed in the vertical and radial planes. It is an open question whether these biases depend on normal visual experience for their occurrence. Here we systematically investigated this issue by testing blindfolded sighted and early blind individuals in a haptic line bisection task. Critically, we found a robust leftward bias in all participants. In the vertical and radial planes, sighted participants showed a consistent downward and proximal bias. Conversely, the directional bias in blind participants was dependent on the final movement direction; thus, there was no general bias in either direction. These findings are discussed in terms of different reference frames adopted by sighted and blind participants when encoding space.     

Verbal instructions targeting valence alter negative conditional stimulus evaluations (but do not affect reinstatement rates)

Negative conditional stimulus (CS) valence acquired during fear conditioning may enhance fear relapse and is difficult to remove as it extinguishes slowly and does not respond to the instruction that unconditional stimulus (US) presentations will cease. We examined whether instructions targeting CS valence would be more effective. In Experiment 1, an image of one person (CS+) was paired with an aversive US, while another (CS?) was presented alone. After acquisition, participants were given positive information about the CS+ poser and negative information about the CS? poser. Instructions reversed the pattern of differential CS valence present during acquisition and eliminated differential electrodermal responding. In Experiment 2, we compared positive and negative CS revaluation by providing positive/negative information about the CS+ and neutral information about CS?. After positive revaluation, differential valence was removed and differential electrodermal responding remained intact. After negative revaluation, differential valence was strengthened and differential electrodermal responding was eliminated. Unexpectedly, the instructions did not affect the reinstatement of differential electrodermal responding.     

I Like You More if I Think You Like Me: The Effect of Metastereotypes on Attitudes Toward People With Deafness

In the present article we aimed at investigating the role of metastereotypes and gender on hearing people’s attitudes towards people with deafness. Ninety-six Italian hearing adults participated in a 2 × 2 experimental study. Participants were presented with the results of a fictitious but apparently real survey concerning the opinions people with deafness have of hearing people. Metastereotypes (positive vs. negative) were manipulated through this presentation. Results showed that metastereotypes interacted with participants’ gender in determining their attitudes towards people with deafness: when positive metastereotypes were activated, women’s attitudes appeared more favorable toward people with deafness if compared to the negative metastereotypes condition. No effect of metastereotypes was observed among male participants. In conclusion, the activation of metastereotypes can be a useful means in intervening to improve attitudes toward people with deafness.