Grant: Discovery Grants Program - Individual

The performance of most tasks with one hand, typically the right, is an intriguing human characteristic. Not only do people prefer to use one hand rather than the other, but they usually perform tasks faster and more accurately with this hand. One notable aspect of hand preference is that certain tasks tend to elicit stronger preferences than other tasks. For example, individuals have strong preferences for the hand they use to write, but show weaker preferences, if any, for the hand they use to turn on a light switch. Likewise, the performance abilities of the preferred hand are superior for certain tasks as compared to the non-preferred hand. Researchers have argued that the reason such lateral asymmetries appear to be task dependent is that the more skill involved in a task the stronger the preference and the greater the preferred-hand advantage a person will demonstrate. However, what constitutes a skilled task is unclear. Therefore, the purpose of the current research proposal is to establish whether the construct of skilled movement may be an underlying determinant of manual preference and performance, and how the construct of skill may relate to other left hemisphere functions. More specifically, the research will a) continue to determine the features that encompass skill and influence the degree of hand preference and the strength of the preferred-hand advantage; b) examine the developmental course of hand preference and performance, particularly with respect to how the identified aspects of skill develop across age; c) determine whether left handed individuals show the same patterns of preference and performance, under manipulations of skill; and d) explore the relation of these identified elements of skill to other lateral asymmetries such as language lateralization. As a great deal of controversy still surrounds the issue of the structure of hand preference and the preferred-hand advantage, closer examination of the determinants of these behaviours will provide insight into the neural specialization of the two hemispheres. This work will ultimately contribute to a theoretical model that will both explain the relationship between handedness and skill acquisition.