We examine the hemispheric organization for the production of two classes of ASL signs, lexical signs and classifier signs. Previous work has found strong left hemisphere dominance for the production of lexical signs, but several authors have speculated that classifier signs may involve the right hemisphere to a greater degree because they can…

To investigate maturational plasticity of fluid cognition systems, functional brain imaging was undertaken in healthy 8-19 year old participants while completing visuospatial relational reasoning problems similar to Raven's matrices and current elementary grade math textbooks. Analyses revealed that visuospatial relational reasoning across this…

Verbal and visuospatial abilities are typically subserved by different cerebral hemispheres: the left hemisphere for the former and the right hemisphere for the latter. However little is known of the origin of this division of function. Causal theories propose that functional asymmetry is an obligatory pattern of organisation, while statistical…

Temporal and spatial attentional deficits in dyslexia were investigated using a lateralized visual temporal order judgment (TOJ) paradigm that allowed both sensitivity to temporal order and spatial attentional bias to be measured. Findings indicate that adult participants with a positive screen for dyslexia were significantly less sensitive to the…

Successful interaction with the environment depends upon our ability to retain and update visuo-spatial information of both front and back egocentric space. Several studies have observed that healthy people tend to show a displacement of the egocentric frame of reference towards the left. However representation of space behind us (back space) has…

Research on spatial thinking impairments, with special reference to right-left orientation, visuomotor and visuoconstructive performances, and finger recognition are examined. It is concluded that, although some dyslexic children do show spatial disabilities, there is little evidence to support the existence of a visuospatial type of developmental…

Sex differences on language and visuospatial tasks are of great interest, with differences in hemispheric laterality hypothesized to exist between males and females. Some functional imaging studies examining sex differences have shown that males are more left lateralized on language tasks and females are more right lateralized on visuospatial…

We assessed 110 left-handed and 322 right-handed children aged from 3 to 10 years, using Bishop's card-reaching task. Manual body midline crossings were observed. A regular developmental trend was observed from 3 to 10 years: older children crossed the body midline more frequently when reaching for cards than did younger children. The factor age…

Moving visual stimuli have been shown to reduce unilateral neglect (ULN), however, the mechanisms underlying these effects remain poorly understood. This study compared lateralised and non-lateralised moving visual stimuli to investigate whether the spatial characteristics or general alerting properties of moving visual stimuli are responsible for…

The extent to which sex differences on a mental rotation test were related to ocular dominance, handedness, and familial handedness was explored. The Vandenberg revision of the Shepard-Metzlar mental rotation test was administered to 206 college students. The test consisted of 20 criterion figures, each followed by two correct and two incorrect…

This study of 34 adults with Down's syndrome found that right-handed subjects exhibited no lateral advantage in dihaptic shape-matching, whereas left-handed subjects displayed an expected left-hand advantage. In a visual field dot enumeration task, both groups exhibited left-field superiority. Results indicate that subjects' atypical cerebral…

Spatial and sequential tasks performed both independently and jointly were compared for 40 undergraduates grouped by sex and dominant hand. When both tasks were performed simutaneously, there was a significant advantage for right-handers and a slight advantage for males. This was attributed to hemispheric interference left-handers experienced.…

A number of cultural and neurophysiological variables were studied to examine their relationship with sex differences in spatial ability. Five paper-and-pencil spatial ability tests were administered to a group of 50 male and 51 female college students, with approximately equal numbers for each sex being left- or right-handed and left- or…

This study compared subjects from right-handed families and nonright-handed families in their ability to solve a mental-rotation task when instructed to use one of two different spatial strategies. Results suggested familial nonright-handers may be stronger in transformation of mental images, but weaker in reorientation in relation to left-right…

The relationships among preferred handedness, family history of sinistrality, sex of subject, and spatial visualization were examined in college students. Males outperformed females at all levels of handedness when measured as a continuous variable. Extreme handedness was associated with poorest performance. Decreased hemispheric specialization…