Display-control stereotype strength of left- and right-handers

Many aspects of the performance of left and right handed persons have been reported. It is generally found that (a) Performance of left-handers, when the workplace is set up according to their handedness, is as good as that of right-handers when using their preferred hand. (b) When using the non-preferred hand, left-handers performance is generally superior to that of right-handers, possibly due to their having had to adapt to a right-handed world. There has been little reported research on the difference of stereotype strength or expectancies of device operation for right- and left handers. This paper reports such research using a set of rotational and translational controls with displays in four different locations relative to the operator. It is found that there was no significant effect of handedness of the participant for horizontally-moving displays and left- and right-handers were equivalent in performance. For vertically-moving displays there were effects of handedness through interaction with controls and display location. Some conditions showed non-equivalence of left and right-handedness in stereotype strength.Relevance to industryAbout 10% of people are left-handed, yet live in a world that is largely designed for right-handers. Experiments are reported to show that, for many combinations of control and displays, there is no significant effect of handedness on stereotype strength.     

The effects of handedness and reachability on perceived distance.

Previous research has suggested that perceived distances are scaled by the action capabilities of the body. The present studies showed that when “reachability” is constrained due to a difficult grasp required to pick up an object, perceived distance to the object increases. Participants estimated the distances to tools with handle orientations that made them either easy or difficult to grasp with their dominant and nondominant hands. Right-handed participants perceived tools that were more difficult to grasp to be farther away than tools that were easier to grasp. However, perceived distance did not differ in left-handed participants. These studies suggest that, when reaching toward a target, the distance to that target is scaled in terms of how far one can effectively reach, given the type of reaching posture that is executed. Furthermore, this effect is modulated by handedness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The grammar of action and reversal errors in children's printing.

36 left-handed and 36 right-handed kindergarten children were asked to print after seeing a series of reversible letters and numbers presented individually on slides or flash cards. Regardless of handedness, both groups of Ss found the left–right orientation cues of the same letters and numbers difficult to recall. This challenges a proposal expressed in the "grammar of action" that claims that certain reversal errors in children's printing result from the inappropriate application of the horizontal motor rule, because although left- and right-handed children use this rule, they do so in different ways and therefore should have produced different errors. Another sample of 86 right-handed children from nursery school through Grade 1 was given the same printing task. Findings from this 2nd sample provide an additional challenge to the grammar of action by showing that reversals of the letter N, which are also thought to result from a misapplication of motor rules, decrease in frequency along with reversals of other letters and numbers, instead of increasing as predicted, during the developmental period when the motor rules that are said to be responsible for reversals of this particular letter become more strongly established. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuropsychological and psychosocial correlates of adult arithmetic deficiency.

The purpose of this study was to examine adult correlates of rule-derived arithmetic deficiency. The authors collected neuropsychological, handedness, gender, and psychosocial data of adults with stringently defined arithmetic deficiency (AD; N=45), reading deficiency (N=45), and dual deficiency (N=45). The authors did not match groups on IQ score and did not restrict analyses to right-handed men. The results indicated that AD in adults is associated with nonverbal reasoning and constructional problems. Otherwise, there was no association between AD and dysphoric complaints as defined by Minnesota Multiphasic Personality Inventory elevations. The authors also found overall intelligence was lower in adults with AD, and gender distribution differed markedly from the reading and dual deficient groups. Potential gender bias in remediation referral patterns was identified. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Frequency-dependent performance and handedness in professional baseball players (Homo sapiens).

I used data on handedness and pitching and hitting performance in annual cohorts of professional baseball players (1957-2005) to test the hypothesis that handedness among pitchers was subject to negative frequency-dependent selection. As predicted by this hypothesis, right-handed pitchers were more successful (i.e., opposing batters hit more poorly against them) when they were relatively rare in the population. Contrary to the predictions of this hypothesis, however, left-handed pitchers were more successful when they were relatively common. Both right- and left-handed batters performed better in years dominated by right-handed pitchers, despite the fact that right-handed batters perform relatively poorly against right-handed pitchers. I suggest that batters form cognitive representations based on pitcher handedness, and that these representations are strengthened by repeated exposure or priming. When the pitcher handedness polymorphism is more balanced (e.g., 67% right-handed, 33% left-handed), these cognitive representations are less effective, which leads to decreased batting averages and improved performance by all pitchers. Furthermore, these cognitive representations are likely to be more critical to the success of right-handed hitters, who have reduced visuomotor skills relative to left-handed hitters. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in left-handedness: A meta-analysis of 144 studies.

Human handedness, a marker for language lateralization in the brain, continues to attract great research interest. A widely reported but not universal finding is a greater male tendency toward left-handedness. Here the authors present a meta-analysis of k = 144 studies, totaling N = 1,787,629 participants, the results of which demonstrate that the sex difference is both significant and robust. The overall best estimate for the male to female odds ratio was 1.23 (95% confidence interval = 1.19, 1.27). The widespread observation of this sex difference is consistent with it being related to innate characteristics of sexual differentiation, and its observed magnitude places an important constraint on current theories of handedness. In addition, the size of the sex difference was significantly moderated by the way in which handedness was assessed (by writing hand or by other means), the location of testing, and the year of publication of the study, implicating additional influences on its development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Increased interhemispheric interaction is associated with earlier offset of childhood amnesia.

Experiment 1 found that mixed-handedness, which is associated with increased interaction between the left and right cerebral hemispheres relative to strong right-handedness, was associated with an earlier offset of childhood amnesia. In Experiment 2, bilateral saccadic eye movements, which have been shown to enhance interhemispheric interaction, were also associated with an earlier offset of childhood amnesia. These results build upon a growing body of research indicating an interhemispheric basis for the retrieval of episodic memories. Moreover, the results of Experiment 2 suggest that interhemispheric interaction has its effect on the retrieval, not encoding, of episodic memories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of a differentiated handedness.

This paper is concerned with the intraindividual differentiation in motoric skill implicit in the development of a "dominant" hand. Its aims are threefold. It attempts to establish a developmentally oriented conceptual framework within which to incorporate diverse observations on handedness, so subordinate findings from several sources to this general framework, and to point out some important gaps in the research literature and proffer some suggestions for future research. Expressions of handedness and hand differentiation are considered as complex phenomena, rooted in more general aspects of motor and psychological development, and very probably multiply and complexly determined in their origins. The introduction of a developmental perspective provides a consistent framework for ordering and simplifying certain kinds of data. (3 p. ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Taking sides.

Reviews the books, Human Laterality (1983) and The Ambivalent Mind (1983)by Michael C. Corballis. These two books explore human cerebral lateralization and handedness, their relationship to each other, and the relationship of both to aspects of cognitive performance. Human Later ality is the better of the two books for the researcher or the professional interested in these topics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)