Brain and Cognition, Elisabeth L. Hill, Fateha Khanem, The Devolepment of Hand Preference in children - Essay Example

In children, when this reaching and clasping requires high degrees of precision, variability of the hand being used in the act decreases considerably, suggesting that children have a clearer preferred hand in those kinds of situations. However, Hill and Khanem (2009) wish to expand the findings of this previous research to understand whether hand preferences in children are developmentally affected by task demands. In addition, if a relationship exists, then the authors also wish to identify the mechanism responsible for changing children’s hand preferences based on their task demands.

The authors bring to attention several lines of evidence supporting their hypothesis. The most important line of evidence is that motor skill is genetically heritable, meaning that manual dexterity is somewhat of a causal factor in the selection of hand preferences in children. In addition, manual dexterity has been proven to increase with age, and children with weak motor skill due to mental illness demonstrated weak hand preference relative to their peers. Both of these evidences point to a reason for hand preference selection in children.

Within that context, Hill and Khanem (2009) set out to measure performance on crossing tasks across the three conditions of QHP (pointing, reaching, and posting) to see if performance is consistent across time and across conditions, which has not been studied in the past. The authors set out to accomplish three aims with this study: first, to replicate or validate findings of an earlier age-related experiment on hand preference using the QHP reaching task, and second, to test the effect of altered task demands (independent variable) on the strength of hand preference (dependent variable) in that same younger age group.

The authors achieved the first purpose, replicating the results of Carlier et al. (2006). With respect to the second purpose, the authors found significant results in how altered task demands affected strength of hand preference in between the reaching vs. pointing and pointing vs. posting tasks. Hill and Khanem (2009) also noted an effect of distance from the midline as an explanatory factor in crossing the midline with the preferred hand. All in all, the results the authors achieved by using the QHP to look at handedness preferences on the part of children revealed a great deal of difference between children’s actual preferences and the hand preferences that their parents rated on an initial questionnaire on their behalf.

While the majority was rated as strongly right-handed, this result did not obtain in the actual QHP task conditions. The authors also allude to a third purpose of this study, which was to investigate the relationship between peg-moving skill and strength of hand preference. As an assessment of manual dexterity, peg-moving skill (and motor maturity in general) is statistically correlated with stronger hand preference. While the authors discovered that peg-moving skill was predictive of a strong hand preference, the speed with which subjects moved the pegs was not predictive of hand preference.

This finding leaves open the question of why the mechanism underlying motor control that is involved in determining strength of hand preference did not respond to the peg-moving task. Before concluding, the authors consider additional avenues of research, including enhancements to