Alcoholism, aging, and functional cerebral asymmetries

Reviews research concerning the possible relationship between cognitive decline and abnormal hemispheric asymmetries in alcoholic and aging individuals. Because the deteriorative effects of alcoholism on the central nervous system have suggested greater visuospatial than language-related functional impairments, numerous investigators had hypothesized that right-hemisphere integrity may be selectively disrupted (rather than the left hemisphere). Furthermore, performance on diverse perceptual and cognitive tests used to measure right-hemisphere functions in alcoholics had been observed to decline with normal chronological aging as well, thereby raising the possibility that certain neuropsychological deficits associated with alcoholism (presumably related to right-hemispheric decline) are identical to those associated with aging. However, an extensive review of empirical research findings on cerebral asymmetries both in alcoholics and in aging individuals suggested that their patterns of functional laterality are similar to those of normal controls.     

Right-hemisphere speech representation and comprehension of syntax after left cerebral injury

Comprehension of language and visuo-spatial abilities were studied in 12 surgical patients with left cerebral lesions and right-hemisphere speech representation verified by sodium amobarbital tests. When left-hemisphere symptoms preceded the acquisition of speech, impaired understanding of syntactically complex sentences was associated with an early, but not late, onset of convulsive seizures. Other behavioral measures did not show a similar effect of age at seizure onset. Sparing or loss of comprehension could not be related to any aspects of the neurological histories in cases with right-hemisphere speech acquired before the onset of left-hemisphere symptoms. Factors which may have influenced the development of right-hemisphere language comprehension are discussed.     

EEG alpha asymmetry and creativity

Results of 3 experiments examining the relationship between creativity and left-hemisphere and right-hemisphere EEG activity are reported. Creativity has been hypothesized to involve the use of primary-process cognition, and such cognition is hypothetically accompanied by activation of the right cerebral hemisphere. In light of these hypotheses, we predicted that highly-creative people should exhibit greater right-hemisphere than left-hemisphere EEG activity during creative performance and that this pattern would not be found in less-creative people. All 3 experiments supported this prediction. This difference in asymmetry was specific to creative performance. It was not present during basal recordings or during a non-creative task.     

Impairment of voice and face recognition in patients with hemispheric damage

Voice and face recognition were tested in 21 left- and 9 right-hemisphere-damaged patients. Test materials were photographs and recordings of famous political and entertainment personalities. Pathological face recognition (prosopagnosia) and voice recognition (phonagnosia) were both significantly more prevalent in the right-hemisphere group. Only one instance of prosopagnosia and one of phonagnosia were observed in the left-hemisphere group, all of whom were aphasic. Of the right-hemisphere cases, there were four instances of each agnosia, with three patients showing a dual impairment. These findings are discussed in relation to differential modes of processing by the two cerebral hemispheres.     

NOTES ON CONTRIBUTORS

Recent literature in the area of psychological differentiation suggests that cognitive styles may have significant application potential to the problems of education. Field dependence/ independence is one cognitive style construct that has a relatively rich history of research and has been given serious consideration for issues involving curriculum and instruction. This article reviews field dependence/independence research as it relates to reading and reading instruction. In particular, the construct is considered from its overall impact on reading, its relation to vocabulary or word knowledge, and its impact on reading comprehension. Implications for reading instruction are developed from the review of the literature and future directions for the interaction of field dependence/ independence and reading research are discussed.     

The Relationship of Cognitive Tempo to Psychological Differentiation and Locus of Control

In this study, we investigated the relationship of cognitive tempo to psychological differentiation and locus of control. The 103 male and female undergraduate students who participated in this study were administered the adolescent and adult version of the Matching Familiar Figures Test, the Group Embedded Figures Test, and the Adult Nowicki-Strickland Internal-External Scale. Using multiple regression analyses, we found that field dependence and independence were significantly related to both cognitive tempo latency and cognitive tempo errors. Contrary to expectation, no relationship was found between locus of control and cognitive tempo. We concluded that psychological differentiation is highly useful in the direct prediction of cognitive tempo, although locus of control is not. Overall, the value of examining cognitive tempo latency and errors separately was upheld. The importance of these relationships is discussed.     

Field independence, lateralization and defensive style

This study investigated the relationship between field independence and defense clustering as measured by the Defense Mechanisms Inventory and lateral eye movements. Subjects had previously been classified either as hysterical or obsessive style by the Rorschach and WAIS Comprehension subtest. Previous findings indicate that these subjects have a preferred direction of lateral eye movement in a questioning format (hysterical style = left; obsessive style = right). This study found no relationship between field independence and defense clustering and lateral eye movements. To the extent that eye gaze indexes hemispheric activation, we conclude that neither field independence nor defense clustering was related to hemispheric lateralization.     

Cognitive styles: illusory phenomena

The relationship between cognitive style and illusion magnitude was examined using the assimilation and contrast Delboeuf distortions. As in previous research, field dependence correlated positively with assimilation; however, a significant negative correlation with contrast was also found, suggesting that, while field dependence may involve the illusory integration of the stimulus field, field independence may involve its equally illusory differentiation.     

The relationship between field independence and sentence disambiguation ability

The relationship between field independence and ability to disambiguate sentences was ivestigated. Sixty-nine college students were administered the Components test of the Flanagan Aptitude Classification Tests as a measure of field independence. Sixty ambiguous sentences, consisting of 15 each of lexical, surface structure, underlying structure, and multiple ambiguity types, were used to assess ability to disambiguate sentences. Results revealed a moderate positive correlation between field independence and sentence disambiguation ability. This relationship suggests (1) that field independence is not a cognitive style limited only to perceptual restructuring processes and (2) that sentential disambiguation processes are not solely a function of linguistic competence.     

The representation of conceptual knowledge: visual,auditory, and olfactory imagery compared with semantic processing

Two experiments comparing imaginative processing in different modalities and semantic processing were carried out to investigate the issue of whether conceptual knowledge can be represented in different format. Participants were asked to judge the similarity between visual images, auditory images, and olfactory images in the imaginative block, if two items belonged to the same category in the semantic block. Items were verbally cued in both experiments. The degree of similarity between the imaginative and semantic items was changed across experiments. Experiment 1 showed that the semantic processing was faster than the visual and the auditory imaginative processing, whereas no differentiation was possible between the semantic processing and the olfactory imaginative processing. Experiment 2 revealed that only the visual imaginative processing could be differentiated from the semantic processing in terms of accuracy. These results showed that the visual and auditory imaginative processing can be differentiated from the semantic processing, although both visual and auditory images strongly rely on semantic representations. On the contrary, no differentiation is possible within the olfactory domain. Results are discussed in the frame of the imagery debate.     

The origins and ends of giftedness

Five issues about giftedness are discussed. First, the origins of giftedness are explored. The view that giftedness is entirely a product of training is critiqued. There is indirect evidence for atypical brain organization and innate talent in gifted children: Many gifted children and savants have enhanced right-hemisphere development, language-related difficulties, and autoimmune disorders. Second, the intense motivation of gifted children is discussed. Third, it is argued that gifted children have social and emotional difficulties that set them apart. Fourth, evidence for the often uneven cognitive profiles of such children is presented. Finally, the relationship between childhood giftedness and "domain" creativity in adulthood is discussed. Few gifted children go on to become adult creators because the skills and personality factors required to be a creator are very different from those typical of even the most highly gifted children.     

Hemispheric asymmetry,early visual processes,and serial memory comparison

Observers indicated whether a single probe letter presented to the left visual field/right hemisphere (LVF-RH) or to the right visual field/left hemisphere (RVF-LH) matched one of two, three, four, or five set letters in both name and case. For positive trials during the initial experimental session, the slope of the linear memory set size reaction time function was increased by perceptually degrading the probe letter on LVF-RH trials, but not on RVF-LH trials. In addition, perceptual degradation of the probe letter increased the intercept of the memory set size function more on RVF-LH trials than on LVF-RH trials. During subsequent experimental sessions, the same pattern of intercept results was obtained but perceptual degradation of the probe no longer changed the slope for either LVF-RH or RVF-LH trials. However, the slopes were uniformly lower on RVF-LH trials than on LVF-RH trials. The major results are consistent with hypothesized right-hemisphere efficiency for early processing stages and left-hemisphere efficiency for serial processing of alphanumeric information. The results further illustrate the importance of separating stages of processing in studies of cerebral laterality and indicate that the relative difficulty of the various stages can be a determinant of laterality results.     

Self-construal, mental distress, and family relations: a mediated moderation analysis with Asian American adolescents

The interactive effects between interdependent and independent self-construal on family cohesion and mental distress were examined. Survey responses from 153 Asian American high school students supported the hypothesized moderation of interdependence by independence on family cohesion, which was found to further mediate the relationship between self-construal and mental distress. Specifically, interdependence was positively associated with family cohesion when independence was high and negatively associated with family cohesion when independence was low. Accounting for the mediator effects of family cohesion, mental distress was positively associated with interdependence and more so for those low on independence than those high on independence. The benefits of biculturalism and research implications for the bidimensional conceptualization of self-construal for ethnic minority populations are discussed.     

Differences in asymmetric perception of facial expression in free-vision chimeric stimuli and reaction time

Two forms of a Chimeric Faces Free-Vision Task used to estimate cerebral asymmetry for perceiving facial expression were given to young male subjects, n = 60 in a first session and n = 40 in a retest session. Test-retest and split-half reliabilities were high. As expected from assumptions of right-hemisphere specialization for processing expression, faces with left-sided smiles were more frequently judged as looking happier than those with right-sided smiles in both forms. However, there were individual differences in direction and extent of bias, which were systematically related to reaction time, right visual field-biased subjects being slower. Differences in lateral bias as well as in reaction time are assumed to reflect individual patterns of hemispheric activation, whereas the average left bias in the present male group may reflect right-hemisphere specialization for processing of facial expression.     

Field independence, academic orientation, and achievement

The Group Embedded Figures Test (GEFT) of field independence was administered to 203 Jamaican sixth form (pre-university) students pursuing advanced-level (A-level) courses with either an arts or a science emphasis. The science-emphasis group obtained significantly higher scores on the GEFT than the arts-emphasis group. In addition, field independence was found to be important for the A-level success of students, regardless of whether they pursued arts- or science-emphasis courses. The implication of this finding to education at advanced level is discussed.     

Dissociative tendencies and right-hemisphere processing load: effects on vigilance performance

The present study was designed to explore the relationship between self-reported dissociative experiences and performance in tasks eliciting right-hemisphere processing load. Thirty-four participants (10 men and 24 women) performed a vigilance task in two conditions: with task-irrelevant negative-arousing pictures and task-irrelevant neutral pictures. Dissociation was assessed with the Dissociative Experience Scale. Consistent with theories positing right-hemisphere deregulation in high non-clinical dissociators, dissociative experiences correlated with greater vigilance decrement only in the negative picture condition. As both the vigilance task and negative picture processing are right lateralized, this result provides support for a right-hemisphere dysfunction in high dissociators, at least in negative conditions.     

Hemispheric processing differences revealed by differential conditioning and reaction time performance.

Two different experimental procedures were used to examine (a) information-processing differences between two groups of subjects (Cs versus Vs) identified by the form of their conditioned eyeblinks; (b) information-processing differences between the right and left cerebral hemispheres; and (c) parallels between hypothesized C-V differences and right-left hemisphere differences. In the first experiment, the evocative command words BLINK and DON'T BLINK served as positive and negative conditioned stimuli. It was found that Vs gave more conditioned eyeblinks than Cs and that differential eyelid conditioning of Vs more than Cs was influenced by the semantic content of the stimuli. More importantly, the conditioning performance of Cs was more influenced by the semantic attributes of the stimuli when they were presented directly to the right visual field (left hemisphere) than when they were presented directly to the left visual field (right hemisphere). In contrast, the conditioning performance of Vs was equally influenced by the semantic attributes regardless of which hemisphere received direct stimulation. A second experiment was designed to determine whether such hemisphere-of-presentation differences for Cs versus Vs could also be obtained in a very different task. Subjects classified as Cs or Vs during a differential eyelid conditioning task then performed two same-different reaction time (RT) tasks that required discrimination of complex polygons in one case and the names of letters in another. On each RT trial both stimuli of a pair appeared briefly either in the center, left, or right visual field. For both Cs and Vs RTs to complex polygon pairs averaged 20 msec faster on left visual field trials than on right visual field trials, consistent with current hypotheses about right-hemisphere specialization for visuospatial processing. In contrast, the results for letter pairs generally confirmed the C-V differences found in Experiment 1. That is, the right visual field (left-hemisphere) advantage for these verbal stimuli was once again larger for Cs than for Vs. The present results suggest that the two groups of subjects (Cs versus Vs) differ qualitatively in the modes of information processing that they typically employ. The results also suggest that these different modes of processing are related to aspects of cerebral hemisphere organization and that even right-handed individuals may differ from each other in the extent to which each cerebral hemisphere is mobilized for a given experimental task. Such individual differences must be incorporated into both models of classical eyelid conditioning and models of cerebral hemisphere specialization.