Laterality on the tapping test among legal offenders

Nineteenth-century ideas on hemisphere differences and “duality of mind”

It is widely felt that the sorts of ideas current in modern laterality and split-brain research are largely without precedent in the behavioral and brain sciences. This paper not only challenges that view, but makes a first attempt to define the relevance of older concepts and data to present research programs.

In the 19th century, there was a body of literature that held that many mental pathologies could be explained by supposing that each individual potentially had two conscious brains. Madness resulted when these begin to interfere with each other or otherwise functioned independently. The left-sided localization of language by Broca in the 1860s complicated matters by showing that the two brain halves functioned differently. Broca argued that functional asymmetry was a reflection of man's capacity to “perfect” himself; soon, the left hemisphere was transformed into the superior, uniquely human side of the brain. Considerable effort then went into seeing how far the functions of the right hemisphere complemented those of the left. The resulting dichotomies of mind and brain interacted—and sometimes also conflicted—with “duality of mind” theories. In the 1880s, the Paris school of neurology helped bring about a revival of interest in these theories with its startling metalloscopy and hemihypnosis experiments.

A section of this target article is devoted to the views of Hughlings Jackson. Jackson's physiological/philosophical writings on hemisphere specialization and mental duality largely set him outside of the rest of the 19th-century tradition. The article concludes that at least some of the data gathered in the 19th century might prove useful or interesting to certain investigators today. More important, it asks how far an awareness of the “time-bound” nature of 19th-century concepts should change the way in which one surveys the laterality scene today.

Cultural and environmental pressure against left-hand preference in urban and semi-urban Malawi

The study assessed views of teachers, pupils and their guardians on left-hand preference. Seventy-five percent of the responders indicated that the left hand should not be preferred for habitual activities and 87.6% of them indicated that left-handers should be forced to change the hand. Gender had significant effect on the view on left hand preference (df = 1, OR (odds ratio) = 0.465, p = 0.027). Giving a handshake when greeting a person, drawing and writing were the three top target activities against left-hand preference. An assumption that the left hand is less skilled and less powerful than the right one was the most common reason for negative view on left-hand use. Most of volunteers reported that parents and close relatives were the primary group of people who usually discourage left-hand use. Eighty point one percent of the responders indicated that people should stop preferring the left hand as soon as somebody noticed their left-handedness. The results indicated that cultural and environmental pressures might significantly affect visibility of left-handedness in urban Malawian populations.

Frontal alpha power asymmetry in aggressive children and adolescents with mood and disruptive behavior disorders

Building on prior research, which has suggested a relationship between aggression and left frontal activity, our study tested the hypothesis that proneness to impulsive aggression would be related to relative left frontal overactivation. EEG one-hertz resting alpha power frontal asymmetry was examined in 65 pediatric male psychiatric patients with a history of impulsive aggression and comorbid mood and disruptive behavior disorders. The strongest finding, which emerged from this analysis, was a finding of relative increases in left frontal activity compared with right frontal activity. The results also indicated that greater left frontal activity correlated positively with the severity of psychiatric disturbance. These findings suggest that relative increases in left frontal activity may be related to a locus of neurophysiological disruption associated with psychopathology characterized by behavioral and affective disinhibition. Results are discussed within a model of behavioral inhibition system-behavioral activation system theory.

Psychopathy--a neurobiological perspective

BACKGROUND

Diagnostic and conceptual issues relating to psychopathy are widely debated, but advances in our understanding of the aetiology are limited.

METHOD

A PSYCHLIT computerised database search of publications covering five decades was supplemented by tracing back through references from existing review work.

RESULTS

Over 200 articles were extracted, and 95 were selected for review.

CONCLUSIONS

It is timely to evaluate the rôle of brain dysfunction. Biological determinants are under-researched and the lack of consistency in operational definitions in published research precludes anything more than tentative conclusions about the genetic, biochemical or electrophysiological correlates of psychopathy and antisocial behaviour. A multi-modal research programme is required in the search for a comprehensive model of psychopathy that can guide both research efforts and clinical interventions.

Strength of handedness as an indicant of delinquent's behavior

In a sample of incarcerated male delinquents (N = 254), dichotomous and continuous measures of handedness were compared in concurrent prediction of delinquent behavior and correlation with past delinquency. The continuous measures proved to be more sensitive indicants of scores on a rating scale of conduct disorder than was the simple dichotomy of left- vs. right-handed. This superiority of continuous measures was not seen on other indicants of delinquency, where sinistrality did not relate to delinquency. Sinistrality was related to the ratings of conduct disorder. No differences on measures of delinquency appeared when strongly and weakly lateralized groups of right- and left-handers were compared.

Neuropsychological and early environmental correlates of sex differences in crime

Results of recent research suggest that longitudinal influences on sex differences in verbal and spatial abilities, and delinquent behavior, may be similar. The present study examined biological, environmental, and psychological variables collected from birth through age 17 on a sample of subjects who participated in the Philadelphia Collaborative Perinatal Project (CPP). Findings supported in part past research suggesting that environmental relationships with intellectual ability and delinquency are strongest for males, whereas biological relationships are somewhat more important for females. Socioeconomic factors were among the strongest predictors of delinquency for both sexes, however. In turn, biological and environmental influences on verbal and spatial abilities and their relationships with later achievement were different between the sexes. Results are discussed in terms of possible sex differences in the development of the left and right cerebral hemispheres, as well as in the vulnerability to environmental influences.

The MMPI'S of left- and right-handed subjects

Previous research has suggested that left-handedness relates to delinquency and violence. In an effort to pinpoint the nature of this apparent relationship, we compared the MMPIs of 72 left- and 687 right-handed men 60 yr. old or less on an alcohol treatment ward. No significant differences appeared. The results are compared to earlier research and hypotheses for further research are suggested.

Handedness and imbalance lateralization on the Tapping Test in MBD children

Twenty MBD children and thirty-eight normal control children were tested for handedness and for lateralization on a Finger Tapping Test. The frequency of nonright handedness in normal children was 16%, whereas it was 60% in MBD children. The significance of this difference was discussed. The "imbalance" hypothesis in regard to the Tapping Test was examined. The hypothesis that "extreme" laterality is more in MBD children than controls was not supported in this study.

Cognitive development and cerebral lateralization in children with learning disabilities

Basic assumptions related to research with learning disabled children are critically examined as they pertain to conceptual models of the relationship between cerebral lateralization and cognitive development. Based on this review, it seems that some assumptions regarding the relationship between cerebral lateralization and cognitive development among learning disabled children are without strong empirical support. Consequently, researchers in this area need to be particularly aware of underlying assumptions related to their research and may need to discuss their results from a more current perspective.

"Optimal" lateralization on the Tapping Test

The present study was designed to test the general "imbalance" hypothesis in regard to the Tapping Test, a motor measure of finger-oscillation speed from the Halstead-Reitan neuropsychological battery. The study was prompted by a recent spate of reports linking cerebral lateralization to a variety of conditions. It was hypothesized that it would be possible to determine an "optimal," midrange of lateralization, to be identified by faster tapping speeds. As hypothesized, those offenders with "moderate" laterality achieved faster speeds than those with "extreme" laterality ("extreme" defined as either less or more laterality than for the moderates). The same range appeared optimal over several demographic groups. A second goal of the present study was to pursue hints from a previous study that had suggested a lateralization measure might prove to be free of some unwanted variations by demographics. As hypothesized, the lateralization measure appeared free of variations according to age, sex, and handedness. Applications and future directions were suggested.

Parietal laterality and violence

To test whether laterality of parietal lobe cerebral functioning might relate to a history of violent behavior, a sample of 33 male and female, right-handed juvenile offenders, divided into less and more violent, each performed the Weighs Test. A lateralization index (left-hand score divided by right-hand score) formed the dependent variable. Differences for sexes and ages, but not ethnicities, required corrections. As hypothesized, poorer right- than left-parietal function related positively with the violence of past crimes. A sample of 18 additional subjects replicated the findings. The results were discussed in terms of a concept of cerebral "area-appropriateness," so that when the task-appropriate area performs less well than a less-appropriate area, we may begin to infer a dysfunction which may relate to "dyscontrol" and to violent behavior.