Cerebral lateralization of spatial abilities: a meta-analysis

There is a substantial disagreement in the existing literature regarding which hemisphere of the brain controls spatial abilities. In an attempt to resolve this dispute, we conducted a meta-analysis to decipher which hemisphere truly dominates and under what circumstances. It was found that across people and situations, the right hemisphere is the more dominant for spatial processing. However, consideration of specific moderator variables yielded a more complex picture. For example, females showed no hemisphere preference while males showed a right hemisphere advantage. Also, no hemisphere preference was indicated for spatial visualization tasks while subjects performing spatial orientation and manual manipulation tasks displayed a predictable right hemisphere preference. These findings are discussed in terms of their implications for exiting theoretical positions as well as future empirical research.     

Cerebral laterality in Turner syndrome: a critical review of the literature.

Turner syndrome (TS) is a genetic disorder in females characterized by the complete or partial absence of one X chromosome. Its most consistent physical features include short stature and ovarian dysgenesis. TS individuals demonstrate a characteristic neurocognitive profile involving weaknesses in visuospatial processing. The hypothesis of defective right hemisphere specialization has been offered to explain the visuospatial deficits in TS. In contrast, an alternative explanation proposes a more uniform dysfunction of the left and right hemispheres, based on findings of symmetrical abnormalities. This article presents an overview of the two hypotheses, along with relevant findings on hemispheric specialization with respect to TS. The impact of the genetic and hormonal mechanisms on the neurocognitive profile of TS is also discussed and directions for further empirical research are identified.     

Cerebral lateralization in bilinguals: Methodological issues

The literature on lateralization for language in bilinguals manifests two apparent contradictions. Some papers demonstrate differences in lateralization between bilinguals and monolinguals; others demonstrate none. In studies with exclusively bilingual subjects, some papers demonstrate differences between the lateralization for the two languages, while others demonstrate none. This paper discusses the range of methodological parameters which must be borne in mind when conducting or evaluating studies of lateralization for language in bilinguals. These include issues of subject selection, language and stimulus selection, testing procedures, data analysis, and interpretation of results.     

The protestant work ethic: A review of the psychological literature

Despite criticism of Weber's thesis concerning the Protestant Work Ethic (PWE) and the rise of Capitalism, few have challenged the specification of the behaviour patterns, goals and values of those adhering to this ethic. Whereas psychologists have not been very interested in the nature of the historical, political and sociological arguments concerning the PWE, they have devoted a great deal of research to its measurement and correlates. In this paper the concept of the PWE; the literature on the instruments devised to measure the PWE; studies on the relationship between the PWE and work and unemployment; as well as research on the PWE and individual differences is reviewed. Despite great heterogeneity in aims, methodology and instruments used in different studies, a coherent picture of PWE beliefs emerges. Finally an elaboration of a new perspective on PWE research is suggested.     

Cerebral lateralization and general intelligence: gender differences in a transcranial Doppler study

The present study evaluated cerebral lateralization during Raven's progressive matrices (RPM) paradigm in female and male subjects. Bilateral simultaneous transcranial Doppler (TCD) ultrasound was used to measure mean blood flow velocities (MBFV) in the right and left middle cerebral arteries (MCAs) in 24 (15 females and 9 males) right-handed normal subjects. The female subjects used a left hemisphere strategy, while males used a right hemisphere strategy to successfully solve RPM tasks. This implies that general intelligence is associated with neural systems within one hemisphere that are accessible to a variety of cognitive processes.     

Exhaled breath analysis in evaluation of psychological stress: A short literature review

Physiological stress is pervasive in today's society. Its detection is normally performed through several unobtrusive methods, driving both caregivers and patients to take measures to reduce the burden of this condition on human health. Among the methods for assessing stress, exhaled breath analysis represents a non‐invasive, real‐time alternative to classic laboratory tests. Therefore, a literature review was performed to assess the presence of altered parameters, related to psychological stress, in exhaled breath. Most studies in our review measured nitric oxide (NO), whose concentration was often correlated, either positively or negatively, with psychological stress, with reasonable scientific support. Other compounds (isoprene, terpene and so on) were rarely studied and with mixed evidence. Further investigations are needed to elucidate the involvement and the pathophysiological role of NO in stress, possibly including a greater number of individuals, as sample size actually represents the main limitation of the work published to date.     

Cerebral lateralization of deaf and hearing individuals for linguistic comparison judgments.

A group of congenitally deaf adults and a group of hearing adults, both fluent in sign language, were tested to determine cerebral lateralization. In the most revealing task, subjects were given a series of trials in which they were fist presented with a videotaped sign and then with a word exposed tachistoscopically to the right visual field or left visual field, and were required to judge whether the word corresponded to the sign or not. The results suggested that the comparison processes involved in the decision were performed more efficiently by the left hemisphere for hearing subjects and by the right hemisphere for deaf subjects. However, the deaf subjects performed as well as the hearing subjects in the left hemisphere, suggesting that the deaf are not impeded by their auditory-speech handicap from developing the left hemisphere for at least some types of linguistic processing.     

Depression and immunocompetence: a review of the literature.

Recent evidence suggests that there is a relationship between depression and immunity. On the basis of these studies, it has been argued that depressed mood may increase susceptibility to disease by means of aberrations occurring within the immune system. Empirical research investigating the relationship between depression and immunity is reviewed here. Studies examining both clinical and nonclinical manifestations of depression are discussed and evaluated. This review reveals that indexes of immunocompetence are lower among people exhibiting depressive symptomology and suggests that immune alterations may be more related to dysphoric mood than to specific situations or events. Alternative hypotheses accounting for links between depressed affect and altered immune states are provided, and suggestions for future research are offered.     

Cerebral lateralization of language in deaf and hearing people

In Experiment 1 neither hearing nor prelingually deaf signing adolescents showed marked lateralization for lexical decision but, unlike the hearing, the deaf were not impaired by the introduction of pseudohomophones. In Experiment 2 semantic categorization produced a left hemisphere advantage in the hearing for words but not pictures whereas in the deaf words and signs but not pictures showed a right hemisphere advantage. In Experiment 3 the lexical decision and semantic categorization findings were confirmed and both groups showed a right hemisphere advantage for a face/nonface decision task. The possible effect of initial language acquisition on the development of hemispheric lateralization for language is discussed.     

Clinical versus actuarial prediction: a review of the literature.

Decisions made by psychologists can have considerable consequences on people's lives. Their decisions could be based on clinical judgment or empirically derived formulas. These two alternatives created a controversy concerning clinical and actuarial prediction. This controversy has been in existence for almost 70 years. During this time hundreds of articles have been published on this topic. This paper contains a review of the findings and issues on clinical versus actuarial prediction. The main conclusions are that (1) linear models are superior to other mathematical models of human judgment, (2) actuarial methods are more accurate than clinical prediction in many situations, (3) human judgment is flawed, and (4) actuarial methods are rarely employed in practice for a variety of reasons.     

Locus of control and biofeedback: a review of the literature.

This paper first reviews studies which have investigated the efficacy of using locus of control orientation to predict performance in various modes of biofeedback. However, contradictory evidence and methodological problems make it impossible to draw any conclusions regarding the connection between internality-externality and biofeedback performance. Second, various attempts to modify externality through biofeedback treatment are reviewed. Although EMG feedback can apparently be used to shift locus of control in an internal direction, there are some major issues that need to be resolved. Of primary importance is the fact that the rationale for modifying externality is based on an unproven assumption that externality has a role in the causation of various undesirable behaviors. Also, as no follow-up testing has been done, there is no evidence that the EMG biofeedback causes relatively permanent, stable locus of control changes. If the shifts are only temporary, then its use as a modifier of externality is questionable.     

Cerebral lateralization of bilingual functions after handedness switch in childhood

Chinese-English bilingual undergraduates who had been forced to switch their preferred hand from the left to the right during childhood were identified. In hemifield perception of Chinese and English words, ordinary left-handers and handedness-switch subjects showed a less strong left-hemisphere advantage when compared with right-handers. The latter showed a significant superiority in identifying words presented in the right visual field. Handedness switch during early childhood did not seem to affect lateralization of language functions, although other motor functions may be affected.