This study was motivated by the emerging hypothesis that right-handers are more strongly lateralized and perform better on various aspects of functional asymmetry than do left-handers. Right-and left-handers •were observed for hand selection responses to a unimanual task of reaching for a small cube in positions of right-and left hemispace, prompting hemispheric decision-making related to hand dominance and attentional (visuospatial) stimuli. As predicted, left-handers did not respond with their preferred limb as consistently across positions as did right-handers. Additional inspection of the task suggests that being less lateralized may not be a disadvantage in this context, and that environmental influence may play a significant role in hand selection for a particular motor event.Resume Cette etude avait pour but de verifier une nouvelle hypothese voulant que les droitiers soient plus fortement lateralises et reussissent mieux que les gauchers dans differents aspects de l'asymetrie fonctionnelle. Nous avons observe la preference manuelle de droitiers et de gauchers au cours d'un test unimanuel ou ils devaient atteindre un petit cube, qui, place soit a droite, soit a gauche, sollicitait la prise de decision reliee a. la dominance manuelle et aux stimuli attentionnels (visuospatiaux). Comme prevu, les gauchers n'ont pas repondu aussi regulierement que les droitiers en fonction de leur region frontale dominante. Un examen supplementaire du test suggere que, dans ce contexte, etre moins lateralise ne constitue pas necessairement un desavantage, et que l'incidence de l'environnement peut jouer un role important dans la preference manuelle pour un element moteur precis.

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This investigation reviewed 14 studies describing the trichotomous distribution of foot preference behaviour spanning early childhood to adult years. Findings suggest that a substantially greater percentage of children are mixed-footed in comparison to older individuals. A significant shift towards right-sidedness appears to occur sometime during late childhood, after which, behaviour remains relatively stable. The incidence of left-footedness is similar across the lifespan. In comparison to handedness, substantially more (about twice as many) young children are mixed-footed compared to mixed-handed. A similar pattern is noted during adolescence and adulthood, but the differences are smaller. Values for leftsidedness (upper and lower limbs) are comparable across the lifespan. Of the existing theoretical models, Annett's Right-shift hypothesis with additional propositions related to environmental influences (Collins, 1977; Porac, 1993; Provins, 1992) provides partial explanation for the findings.

Foot preference and performance characteristics of gross-motor lower-limb speed of tapping were examined in 606 4- to 6-yr.-olds. Analysis indicated no effect for gender; however, speed of foot tapping increased significantly across the three ages, suggesting an association with selected developmental (neuromuscular) processes. Contrary to earlier reports on handedness, there was no statistical evidence that mixed- or left-footers were at a performance disadvantage compared to right-footers. All groups performed best with the right foot, limb differentiation (right versus left) being significant for the right- and mixed-footed groups. Speculation about maturational and environmental influences is given.