Elsevier

Brain and Cognition

Volume 71, Issue 2, November 2009, Pages 99-107
Brain and Cognition

The development of hand preference in children: The effect of task demands and links with manual dexterity

https://doi.org/10.1016/j.bandc.2009.04.006Get rights and content

Abstract

Lateralisation of hand preference and manual dexterity are known to develop over childhood, while in adulthood strength of hand preference has been shown to interact with extrinsic task demands. Some evidence exists to suggest that strength of hand preference and motor skill may be related. In the current study a handedness inventory, midline crossing (QHP) and peg-moving tasks were used to investigate: (1) the development of hand preference between 4 and 11 years; (2) whether extrinsic task demands affect strength of hand preference, and (3) whether strength of hand preference was associated with manual dexterity. Younger children (4–5 years) showed weak hand preference in comparison to older children (8–11 years), and extrinsic task demands influenced willingness to cross the body’s midline with the preferred hand. Age and peg-moving speed were associated with midline crossing in certain task conditions. Overall, results suggest a coupling between manual dexterity and brain maturation in typical development.

Introduction

Numerous studies of hand preference have been published over the decades, focusing on a range of issues including heritability, developmental disorders and brain organisation (lateralisation). For the most part, researchers have used preferred hand for writing, or handedness questionnaires to assess an individual’s hand preference. Overall, some people have a higher degree of hand preference than others and tend to use one hand exclusively for all activities. Others, although pre-dominantly right- or left-handed, will use their non-preferred hand for some activities.

Traditionally, questionnaires were used to evaluate hand preference by asking people to specify hand preference across a range of activities (e.g., Edinburgh Handedness Inventory; Oldfield, 1971). While this can provide useful information, there are some drawbacks since questionnaires are subjective, may contain items associated with social pressure and may have different meanings for left- and right-handers. To get round these factors, Bishop, Ross, Daniels, and Bright (1996) developed an objective measure in which a behavioural continuum was used to measure strength of hand preference. This measure is known as the quantification of hand preference (QHP) task. In the first version of this task, participants were observed picking up cards placed at each of seven locations in extrapersonal space, with one location set at the body midline, three locations placed in contralateral space and three locations in ipsilateral space (see Fig. 1). The hand used to make each reach was recorded and the number of right-hand reaches (in right-handers) summed and used as an index of strength of hand preference (100% of reaches would be made using the right-hand by an exclusive right-hander, and 50% of reaches would be made with the right-hand in somebody with no hand preference). In this task, willingness to use the preferred hand to cross the midline and reach to cards in contralateral space is thus an indication of strength of hand preference. Bishop et al. showed that their task discriminates between degrees of handedness within the right-handed population (i.e., discriminating between strong and weak right-handers). Furthermore, Calvert and Bishop (1998) showed that the QHP task discriminated additionally within groups of left-handers, as well as between groups of left- and right-handers.

A number of studies have reported tasks of midline crossing in children and these have shown that older children, like adults, cross the body midline more frequently when reaching for cards than younger children (e.g., Carlier et al., 2006, Cermak et al., 1980, Hill and Bishop, 1998, Stilwell, 1987), although only the two most recent of these studies have used the QHP task.

According to Fagard and Lockman (2005), task constraints influence the expression of handedness, especially in children. When grasping requires precision, the variability of the hand used decreases, and use of the preferred hand is more clearly observed. Calvert and Bishop (1998) illustrated this in adults by carrying out three variations of the QHP task: reaching (the original QHP task, reach for a card at one of seven locations and place in a central box), pointing (point to a card at one of seven locations) and posting (pick up a marble from a central location and place into a container at one of seven locations). In this study the spatial position of an object and the task demands affected strength of hand preference (i.e., how often a midline crossing was made). Given the evidence of increases in midline crossing on a reaching task with age in typical children (Carlier et al., 2006, Hill and Bishop, 1998), the question is raised as to whether task demands affect hand choice in typical development, and if so, what mechanism might support this change.

A number of strands of evidence point to manual dexterity as a potential correlate. Bishop (1990) suggested that the development of a consistent hand preference might depend on maturation of skilled motor performance. This suggestion is supported in two ways. First, manual dexterity improves with age in typical development (e.g., Kilshaw & Annett, 1983). Second, children with developmental coordination disorder (DCD), which is diagnosed on the basis of poor motor skill, showed weak hand preference on the QHP reaching task in comparison to age and IQ matched controls (Hill & Bishop, 1998). In the same study, children with specific language impairment (SLI) showed weak hand preference in comparison to the control group. It should be noted that this was true both of children with SLI who performed poorly and those performing in the normal range on a standardised test used to identify motor impairment. However, given that motor performance can vary from task to task (Calvert & Bishop, 1998), it is not totally clear that those children who did well on the motor test battery would be considered unimpaired motorically if assessed on a larger range of tasks.

Genetic evidence may also hint at an influence of motor skill. In a twin study in which twin pairs with and without language difficulties were assessed on the QHP reaching task, Bishop (2005) showed that the QHP task, but not a handedness inventory, showed modest, but significant heritability. In an earlier study Bishop (2002) reported a shared genetic influence of motor skill (assessed using a tapping task) and speech production in a twin sample of children with and without SLI. Furthermore, Francks and colleagues have reported two molecular genetic studies showing linkage of relative hand skill on a peg-moving task to a quantitative trait locus on the short arm of chromosome 2 (sib-pairs sample, Francks et al., 2002; left-handed brothers sample, Francks et al., 2003a). Taken together, such findings suggest potential for manual dexterity to be a causal factor in the development of strength of hand preference. While the current study was underway, Doyen, Dufour, Caroff, Cherfouh, and Carlier (2008) published a study in which they compared performance on Annett’s peg-moving task with performance on the QHP card reaching task in participants aged 6–51 years of age. Younger children showed an increase in willingness to make midline crossings with the preferred hand but after 12 years, this performance dropped off. Doyen et al. argued that this finding suggests that initially the development of manual dominance is an important contributor to the decision to reach across the body’s midline. However, with age the task becomes simple and participants are equally willing to reach into ipsilateral space with each hand. This account is supported by findings on the QHP reaching task from individuals with neurodevelopmental disorders associated with immature motor skill such as DCD (Hill & Bishop, 1998), SLI (Hill & Bishop, 1998), Down syndrome (Groen, Yasin, Laws, Barry, & Bishop, 2008) and Trisomy 21/Williams Beuren syndrome (Gérard-Desplanches et al., 2006). However, all of the studies cited above focused only on the card-reaching QHP task. In the current study, all three QHP task conditions (pointing–reaching–posting) were used in order to establish whether the altered task demands of these three QHP conditions would require varying levels of manual dexterity skill for successful completion. If performance across these conditions is shown to change over the course of development, it is plausible that commensurate improvements in manual dexterity skill will be associated with this. To the best of our knowledge, no direct study has been conducted to consider this possibility within the typical population.

Understanding the mechanisms that support the development of strength of hand preference is an important research question since it can shed light not only on the mechanisms associated with increased lateralisation (indexed by midline crossing), but also provide some insight into the nature and causes of poor lateralisation in those with neurodevelopmental disorders (e.g., Bishop, 2005, Groen et al., 2008, Gérard-Desplanches et al., 2006, Hill and Bishop, 1998). To this end, the current study built on previous studies of reaching tasks using midline crossing. It had three aims. First, the study aimed to replicate the finding of age-related changes in strength of hand preference when completing the QHP reaching task. Second, developmental changes in strength of hand preference were investigated when the QHP task demands were varied, involving greater or lesser degrees of fine motor control (post, reach, point, respectively). Third, the relationship between strength of hand preference and manual dexterity skill, indexed through a peg-moving task, was investigated. It was hypothesised that reduced variability in children’s hand preference would be associated with increasing manual dexterity, particularly in the posting condition which requires a greater degree of manual dexterity (indexed by a greater likelihood of midline crossing with the preferred hand in this condition).

Section snippets

Participants

A total of 100 typically developing children participated in the study. All were recruited from an ethnically diverse East London primary school (UK). Children were aged between 4 and 11 years (mean 7.9 years, SD 2.1), and were grouped into four age bands: 4–5 years, 6–7 years, 8–9 years, and 10–11 years. All children were typically developing physically and academically as judged by their teachers. None showed exceptional skills in any domain and none had been diagnosed with any form of

Writing hand

There was no significant difference in hand preference either between the four age groups [χ2(3) = 2.34, p = .504] or the two gender groups [χ2(1) = 0.41, p = .84] (see Table 1).

Handedness questionnaire

The mean laterality quotient (LQ), and distribution of LQs calculated from the Edinburgh Handedness Inventory are shown in Table 2. There was no significant difference in the LQ scores between either the age groups [χ2(3) = 5.758, p = .124] or the two gender groups [χ2(1) = 15.51, p = .488].

Quantification of hand preference tasks (QHP)

The frequency of right-hand reaches was

Discussion

The current study was set up to investigate the development of hand preference in children, and whether task constraints affect reliance on the preferred hand. The first aim of the current study was to replicate Carlier et al.’s (2006) finding of age-related changes in strength of hand preference when completing the QHP reaching task. This finding was replicated in a sample of 4–11 year old, typically developing children. Like Carlier et al., our data also replicate findings using other midline

Acknowledgments

We are grateful to the headteacher, staff, parents and children of Malmesbury Primary School, Tower Hamlets, London for their willing participation in this study.

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