Degree Of Hand Preference Research Articles

Hand preferences and hand ability in congenitally blind children.

Congenitally blind and sighted blindfolded children between the ages of 6 and 14 years were tested for hand preference with performance tasks. There were no differences between the groups in direction or degree of hand preference. The degree of handedness increased with age and was essentially linear though the blind seemed to be somewhat less lateralized at the younger ages. When the same groups were required to match three-dimensional bricks for height, depth, breadth, and volume, no hand advantages were found for either group. Both groups of children improved in their accuracy of spatial discriminations with age. Further, the degree of lateralization on the handedness task did not relate to ability on the tactile task or to differences between the right and left hands on the tactile task. Thus, there is no effect of blindness on tactile matching ability nor is there an effect of the hand used in the task.

Relationship of serum zinc levels to hand preference, skull length and serum gonadal hormone levels in right-handed young adults.

The association between serum zinc (Zn) level and the degree of hand preference was studied in right-handed young adults. Hand preference was scored by the Waterloo Handedness Questionnaire. Serum Zn level was determined by the flow injection analysis-atomic absorption technique. Zinc was found to be positively linearly and significantly correlated with the degree of right hand preference in the sample of males with familial sinistrality (FS+) and FS- females with right eye and right foot preference. There was a negative linear correlation between these variables in FS+ females. Skull length showed a significant negative linear correlation with zinc in FS+ males and females, but a positive linear correlation in FS- females. In FS- females, there was a significant positive linear correlation between serum gonadal hormone binding globulin (GBG) and serum Zn levels. In FS+ males, there was a significant negative linear correlation between serum GBG and Zn levels, and a significant positive linear correlation between serum free testosterone level and serum Zn level. It was suggested that zinc may influence the degree of the right hand preference by hormonal mechanisms according to genetically established brain organization.

The relation of body height to handedness in male and female right- and left-handed human subjects.

The association between body size and the degree of hand preference was studied in male and female right- and left-handed human subjects. Hand preference was assessed by the Edinburgh Handedness Inventory. In left-handers (total sample), there was a significant, negative linear correlation between the degree of left-hand preference and body height. There was no significant correlation between these parameters if the males and females were considered separately. In right-handers (total sample), body height was found to be significantly and negatively linearly correlated with the degree of right-hand preference. A similar correlation was observed in males without familial sinistrality (FS-) and in FS+ females. There was no significant correlation between these parameters in FS+ right-handed males and FS- right-handed females. It was suggested that hormones affecting body height and brain size such as human growth hormone and testosterone would also contribute to the development of cerebral lateralization.

Reliability of hand preference items and factors

The present study examined the test-retest reliability of a 32-item version of the Waterloo Handedness Questionnaire (Steenhuis & Bryden, 1987, 1988, 1989) on 500 subjects. The questionnaire was shown to be reliable in terms of basic factor structure. High test-retest reliability was also found within subjects' responses and across items for both right-handers and left-handers, although left-handers were less consistent than right-handers, particularly with regard to direction of hand preference on individual questionnaire items. Furthermore, the direction of hand preference was more reliable than was the degree of hand preference. These data support a multidimensional view of hand preference in which both direction and degree can be reliably assessed.

Relation of testosterone and hand preference in right-handed young adults to sex and familial sinistrality

The relationship between serum testosterone level and the degree of hand preference was studied in right-handed young adults. Hand preference was assessed by the Edinburgh Handedness Inventory. Serum testosterone level was determined using tritium-marked-radioimmunoassay. There was no significant correlation between these variables in males without FS. In males with FS and in females with and without FS, the serum testosterone levels were found to be negatively linearly correlated with the degree of the right-hand preference. Similar results were obtained with respect to foot and eye preferences. It was concluded that not only prenatal testosterone but adult testosterone also may exert a life long influence on cerebral lateralization; this effect seems to be much more pronounced in the female than male brain, which may exert a female-like pattern under genetic control.

Mirror Image Discrimination and Hand Preference in the Bushbaby (Galago senegalensis)

Eight Galago senegalensis were tested for mirror image confusion and hand preference. The mirror image test consisted of two visual discrimination tests performed in a Yerkes two-choice apparatus and presented in a counterbalanced order. In one test discriminanda were mirror image forms and in the other, nonmirror forms. Half the animals saw stimulus pairs presented sequentially and half saw them presented simultaneously. Handedness was measured by presenting the animals, who were confined in a small holding cage, with mealworm on the end of a rod. No difference was found between simultaneous and sequential groups. Mirror images proved more difficult than nonmirror images, using a one-tailed sign test (x = 1, n = 8, p =.05). Seven of the animals showed consistent preference for the left hand. There was no correlation between degree of hand preference and degree of mirror image confusion based on absolute error scores (r =.14) or error difference scores (r =.02). No support was found for the hypothesis that mirror image confusion is related to poor lateralization.

Handedness and right-left discrimination.

Hand preference in manual activity has long been a topic of investigative interest because of its association with the language functions and the concept of cerebral dominance. Similarly, the ability to discriminate between the right and left sides of one's body has claimed attention, although to a lesser degree than is the case with handedness. Psychologists have utilized measures of discrimination as an index of general intelligence and in the genetic study of children's conceptions of space. Neurologists have been particularly interested in the ability ever since the demonstrations by Bonhoeffer (4) and Gerstmann (6) that impairment in discrimination is not only related to the presence of cerebral disease but also may possess localizing significance. While disorientation in pure form (i.e., unaccompanied by more profound disturbances in the body schema) is rather uncommonly encountered in adult patients with cerebral disease, recent investigative work (i) suggests that it may occur in a clinically significant proportion of brain-injured and defective children. The question arises as to whether there is a relationship between these two aspects of laterality or right-left behavior, the motor aspect being represented by degree of hand preference and the perceptual aspect