In an effort to explore S. Orton's "intergrading" hypothesis, six developmental dyslexics (ages 16 to 47) and four good readers were tested on measures of interhemispheric coordination. Dyslexics showed reduced laterality bias and longer response latencies to bihemifield stimuli. (Author/DB)

Compared four-year-old left-handed children and children lacking definite hand preference with right-handers on motor skills. Found no differences between left-handers and right-handers of either sex, but the children lacking hand preference had lower scores. Possible sex differences and implications for the education of children lacking…

This commentary, written in response to Witelson's work (1987), examines alternative ways of determining how the developmentally stable functional asymmetry (hemispheric specialization) observed in neurologically intact children can be reconciled with the dramatic recovery of function often displayed following unilateral brain damage. (PCB)

Examined were electroencephalogram (EEG) asymmetries during the presence of discrete facial signs of emotion among 10-month-old infants who were tested in a standard stranger- and mother-approach paradigm that included a brief separation from mother. Data underscore the usefulness of EEG measures of hemispheric activation in differentiating among…

Left-hemisphere language specialization in right-handed children was tested in children previously classified as consistent or nonconsistent in their hand preference. Results showed that both male hand preference groups demonstrated asymmetric interference in dual task tapping performance. In contrast, only females associated with consistency in…

This paper examines the influence of Norman Geschwind's model of connectionism, in which complex functions are built up by connecting primary areas in the brain, and notes his studies of the effects of disconnection on dyslexic individuals. Connectionist-based behavioral studies are reviewed, focusing on intracortical association connections and…

This study, involving adults with and without mental retardation and mental age-matched children, employed a lateralized presentation of Stroop color words, neutral words, and the subject's first name. Individuals with mental retardation experienced difficulty in effortful processing (inhibiting the reading response on the Stroop trials) and in…

Discusses the relevance of the study of the neurobiology of cognitive development, for an understanding of both the neural bases and the nature of cognition. Also considered are the age at which hemisphere specialization first appears and whether hemisphere specialization changes over time. (PCB)

A study of children (ages 3-5 and 11-13) with autism (n=35), learning disabilities (n=26), or no disabilities (n=90) found that the nondisabled children were more lateralized than others in degree and consistency of handedness. No evidence was found of a dissociation of hand skill and hand preference in children with autism, compared to others.…

This paper reviews literature on the use of dichotic stimulation in individuals with mental retardation, and examines how noninvasive dichotic stimulation relates to hemisphere lateralization. Common findings are discussed concerning direction and magnitude of ear asymmetries, patterns of intrusion errors, and speech lateralization of Down…

Family histories of 12 hyperlexic (precocious word reading with little comprehension often associated with autism) children (5-10 years old) were investigated. Results suggested familial tendencies to disorders of language, reading, writing, and spelling in male relatives, along with a high incidence of nonright-handedness. (Author/DB)

Two enduring questions in psychology concern the effects on behavior of traits and of attitudes. One method of altering the relative influence of traits or attitudes is by manipulating the activity of those areas of the brain which attend more to the self or to the external environment. Two experiments were conducted to test whether manipulation…

Brainstem auditory evoked response latencies were studied in 80 males (13 with Down's syndrome). Latencies for waves P3 and P5 were shorter for Down's syndrome subjects, who also showed a different pattern of left versus right ear responses. Results suggest decreased lateralization and receptive and expressive language ability among people with…

Research supports the premise that various mathematical topics can be categorized as being performed better by the left or right brain hemisphere. This study examined the effect of left and right brain hemispheric lateralization exercises upon course grades in two sections of Analysis I (beginning calculus for mathematics/science majors) at a…

Research supports the premise that various mathematical topics can be categorized as being performed better by the left or right brain hemisphere. Hemispheric lateralization is defined as a learner's preferred hemisphere of control. Torrence's "Human Information Processing Survey" was given to 170 black female college students enrolled in…