Lateral preference patterns as possible correlates of successfully switched left hand writing: Data and a theory

Abstract

Left-handers often have had to contend with pressure to switch their preferred writing hand and shift attempt reports are common, especially among older adult left-handers. Three groups of left-handers can be defined by combining two variables, writing hand side and the report of a rightward hand preference shift attempt. The three groups are, first, right hand writers who report a rightward shift (successfully shifted left-handers); second, left hand writers who report a rightward shift attempt (unsuccessfully shifted left-handers); and, finally, left hand writers who do not report a rightward shift attempt. The underlying mechanisms that determine the success or failure of a handwriting shift attempt remain unclear. The present study examined the history of attempts to switch the preferred writing hand in a sample of 1277 adults aged 65 to 100 years of age. Older adults are well suited to participate in such a study because pressure to switch hand preference was especially severe for those who grew up in the early part of the 20th century; reports of rightward shift attempts are more common in this age group than among younger adults. Our results suggest that the three groups of left-handers, distinguished by the presence or absence of a shift history report and writing hand side, can also be distinguished from each other on the basis of their overall lateral preference profiles (the sides of hand, foot, eye, and ear preferences). Left hand writers, with and without reports of a rightward shift history, showed stronger left side lateralisation patterns when compared to right hand writers who reported a rightward switch (the successfully shifted left-handers).

Hand preference and skilled hand performance among individuals with successful rightward conversions of the writing hand

“…They found that these other lateral preferences were shifted towards the right side when successfully switched left-hand writers were compared to the two groups who wrote with the left hand. Searleman and Porac (2001), p. 312) interpreted these results as ''indicating that left-handers who successfully shift to righthand writing are following a 'natural' right-sided lateralisation pattern that they already possess. By changing the preferred writing hand, it allows them to conform to a pre-existing right-sided lateral preference template''.…”

“…There are reports that relatively large numbers of adult left-handers have experienced attempts to switch writing hand to the right side (Porac & Searleman, 2002;Searleman & Porac, 2001). Some of these individuals switch successfully and write with the right hand while others remain lefthanded for writing.…”

“…One of the most interesting questions remaining unanswered in the study of successfully switched left-handers is why some individuals succumb to these pressures while others do not (Meng, 2007). Searleman and Porac (2001) addressed this question by comparing the sidedness patterns of foot, eye, and ear preference among successfully switched left-hand writers, left-hand writers with no switch pressure history, and left-hand writers who did not switch when pressured. They found that these other lateral preferences were shifted towards the right side when successfully switched left-hand writers were compared to the two groups who wrote with the left hand.…”

Handedness of children determines preferential facial and eye movements related to hemispheric specialization

“…Asymmetry in human cerebral hemisphere function, as reflected in a special relationship of the left hemisphere to language, has been recognized for more than a century 1 . Subsequent observations have identified other aspects of lateralization in brain tasks, such as the superiority of the right hemisphere for spatial manipulations.…”

Adaptations of writing posture in response to task demands for left- and right-handers

“…If inverted posture is indeed an appropriate and useful adjustment, why do so few lefthanders make this adjustment in their usual writing? Given that children make the posture choice quite early in development (Bryson & MacDonald, 1984;Gaillard, 1992;Peters, 1986;Peters & Pederson, 1978), it was presumed that in children an unusual behaviour like left-handedness or like an inverted hand posture would be a target for intervention leading to modification (Porac & Buller, 1990;Porac et al, 1986;Searleman & Porac, 2001). Just as left-handers were induced to become right-handed, inverters may have been induced to use a standard posture (e.g., see Blau, 1946;Eager, 1974, for``how to'' instructions for left standard and against inverted postures).…”