Gender Differences In Visual And Tactile Line Bisection Running Head: ATTENTIONAL BIAS IN NORMAL SUBJECTS Gender Differences in Visual and Tactile Line Bisection: Attentional Bias in Normal Subjects Abstract Attentional bias in line bisections may be influenced by the position of the stimulus, the type of stimulus, and the gender of the bisector. Past research has found that below eye level bisection stimuli is biased away from the body in the visual mode, and towards the body in the tactile mode. Above eye level bisections have not been significantly biased in either direction due to a cancellation of the object centered bias by the body centered bias. Research has also concluded that no gender differences are statistically significant in attentional bias studies, using line bisection tasks. This report suggests that gender differences are statistically significant in favor of male subjects, when using above eye level stimuli, and when using tactile stimuli. Overall, however, these differences become statistically insignificant, when combined with below eye level tasks and visual tasks.
Current findings also point to a trend towards supporting past research findings which state that in below eye level bisections both males and females are biased away from the body in the visual mode, and towards the body in the tactile mode. Gender Differences in Visual and Tactile Line Bisections: Attentional Bias in Normal Subjects The act of survival requires humans to pay attention to their surroundings. In order to pay attention to surroundings, one must allocate resources of attention to the space around one’s body. Taking a common sense approach, the sense of vision and the sense of touch would be the candidates for “most important senses in terms of survival”. For example, imagine a primitive hunter trying to catch prey, using only his sense of smell; or imagine someone trying to build a hut, without the use of sensitive fingers to wield tools.
Vision is generally used as a means to detect and interpret objects at a distance, whereas, touch is used to detect and interpret objects which are relatively close to the body. Historically, visual and tactile attention have been studied along a left-right horizontal axis (Shelton, Bowers, & Heilman, 1990 as cited in Geldmacher & Heilman, 1994); however, there has been a recent expansion of this research, into the vertical and radial axes. The current study will attempt to confirm the findings of Geldmacher and Heilman (1994), Jeerakathil and Kirk (1994), and Drain and Reuter-Lorenz (1996) that below eye level bisection stimuli will be biased away from the body (far peripersonal space) in the visual mode, and towards the body (near peripersonal space) in the tactile mode. Above eye level bisections should not be significantly biased, however, due to a cancellation of biases – i.e., the object centered bias nullifies body centered bias. Drain and Reuter-Lorenz (1996) are one of the only research teams to have considered gender as a factor in the results of such studies.
They concluded that although gender does contribute to real sex differences, it is not a significant factor in assessing attentional bias in normal subjects on line bisection tasks, due to the minuteness of these differences. However, given the common perception that males are superior to females in tasks of visuo-spatial dexterity (Maccoby & Jacklin, 1974, Caplan, MacPherson, & Tobin, 1985, Newcombe & Dubas, 1992, all as cited in Dworetzky, 1996), it should be a natural to examine the results of men vis–vis women. Thus, in the spirit of gender equality and the pursuit of confirming such a hypothesis, the current study will include gender as a factor of analysis. In 1994, Geldmacher and Heilman studied 10 normal subjects in radial line bisection tasks. That is, they had participants determine where the middles of lines were, when the lines ran outward from the subjects’ bodies, on a horizontal plane.
They found that significant near peripersonal misbisections occurred in the above eye level tasks. Whereas, far peripersonal misbisections were replicated in the below eye level tasks. Further, Jeerakathil and Kirk (1994) found similar results. Their study showed significant bisection biases towards the TOP (they used labels at each end of stimulus lines: TOP, BOTTOM) of both horizontal and vertical lines, as well as in the below eye level radial condition. Again, the bias towards far peripersonal space in the below eye level condition was nullified when the stimuli were presented above eye level. Kageyama, Imagase, Okubo and Takayama (1994), looked at vertical and radial neglect in unilateral brain damaged patients.
They concluded that neither vertical nor radial neglect can be explained by visual field defect, because some of the participants in this study did not have visual field defect, but they consistently displayed far or near peripersonal bias in radial line bisections and superior vertical neglect. Thus, the results tend to support the attentional bias theory of line bisection. This study will be based on previous works by Heilman and other research teams, in the area of visual and tactile line bisection and the pursuit of attentional biases. It is expected that the results will show a difference in mean line bisection error (LBE) in favor of the male participants, thus confirming the common perception of male superiority in visual spatial tasks, versus women. Method Participants Four men and eight women participated in this study.
They are students at Simon Fraser University, in a Psychology 303 course. All are participating as part of their class participation mark, as well as a reciprocal subject cooperative. The researcher should have confirmed that all subjects have normal vision (corrected if necessary), no neurological deficits, and no history of brain injury or trauma, however, due to time constraints, these possible confounds were not accounted for. Materials Single, 3mm wide, black lines drawn in the center of 8.5 x 11 in. white paper were used as the visual stimuli (see Appendices A, B, C).
Increasing in increments of 5 cm, three lengths were used, ranging from 10cm-20cm. According to Kageyama et al. (1994), multiple line lengths will minimize the possibility of motor set effects from repeated identical length stimuli. These sheets were taped to a table in the below eye level condition (30cm from the body), and were held at a predetermined distance (30cm) from the body by the researcher, in the above eye level condition. The tactile stimuli consisted of nylon string (approx. width=3mm; approx.
height=3mm) glued to 8.5 x 11 in white paper (see Appendix D). This paper was then attached to larger cardboard to provide rigidity in the above eye level condition. The tactile stimuli ranged from 10cm – 20cm with 5cm increments, identical to the visual stimuli. In all, four test conditions occurred, visual above eye level (VA), visual below eye level (VB), tactile above eye level (TA), and tactile below eye level (TB). In each condition, all three lengths were tested in a random order.
Design and Procedure The current study is a mixed design, due to the calculation of results with …