PL2131: Research & Statistical Methods 1 - Lab Report

Running Head: GENDER AND SPATIAL ABILITY

Gender Differences in Spatial Ability

Tan Jia Xin Jacinth

National University of Singapore

Abstract

The aim of this study was to investigate whether there are significant gender differences in performance on a spatial ability task. One hundred and thirty-eight undergraduate students were administered the Vandenberg and Kuse (1978) Mental Rotations Test. The task consists of 20 problems, in which a picture of a three-dimensional primary object was presented with a set of four dissimilar objects in each problem. Only two out of the set of four are the same as the primary object and participants had to identify and select the correct two for as many problems as they can under a given time limit. At the end of the test, their scores were calculated and compiled. An independent samples T-test was performed on the data and the analysis suggested a significant difference between male and female participants in their Mental Rotations Test scores.

Gender Differences in Spatial Ability

Numerous literatures have reported disparity between males and females in their performance on various spatial ability tasks, with males at an edge over females in general (e.g., Collins & Kimura, 1997; Roberts & Bell, 2000). Some biological basis had been suggested to account for such differences, one of which being higher levels of testosterone in males which “influences abilities related to the encoding, comparison, initiation and/or decision processes” (Hooven, Chabris, Ellison & Kosslyn, 2004) that are involved in spatial ability tasks such as Mental Rotation. Another reason was that women in their midluteal phase have higher estrogen and progesterone levels as opposed to the menstrual phase, which reduces spatial ability (Hausmann, Slabbekoorn, Van Goozen & Kettenis, 2000). Nevertheless, some studies have found exceptions where women outperformed men in spatial ability tasks (Casey & Brabeck, 1990). They proposed an interaction of genetic and environmental factors where “right-handed women from non-right-handed families” who had been predisposed to “Masculine gender-typed activities such as carpentry, work with electrical circuits, or building model airplanes” tended to excel in spatial ability tasks (Casey & Brabeck, 1990). With the above findings in mind, the present study purports to test the hypothesis that significant gender differences on spatial ability task, specifically in mental rotation, exist.

Method

Participants

One hundred and four female and 34 male undergraduate students participated in the study. All participants performed the Mental Rotations Test during their respective classes in the computer laboratory of the Psychology department.

Materials

A six-page, revised version of the Vandenberg and Kuse (1978) Mental Rotations Test was used in the study.

Procedure

Participants were asked to perform the Mental Rotations Test. The paper-and-pencil task consists of 20 problems, where a picture of a three-dimensional primary object was presented together with a set of four dissimilar objects in each problem. Only two out of the set of four are the same as the primary object and participants had to identify and select the correct two by marking Xs in the boxes under them.

The test was divided into two parts, Part I and Part II, with 10 questions each. Participants were given three minutes to attempt each part and a one-minute break was allocated in between the two parts.

At the end of the test, participants had to check their answers against the answer key and determine the number of correct and incorrect objects identified by them. For every correct answer, one point was awarded, whereas for every incorrect answer, half a point was deducted, so as to correct for guessing. Finally, the individual and total scores for Parts I and II were calculated.

Results

The mean score for males was 20.8 with a standard deviation of 7.2 while the mean score for females was 14.98 with a standard deviation of 7.26. An independent samples T-test analysis indicated that the difference in performance on the Mental Rotations Test between both genders was significant, t(136) = 4.05, p<.05, d = 0.80.

Discussion

The results of the study supported the hypothesis that there are significant gender differences in performance on spatial ability task, specifically in mental rotation. The mean score of males was also substantially higher than that of females, indicating that males actually outperformed females in the task. As such, the results appear to be a replication of the extensive literatures which have suggested that males are more adept at spatial ability tasks.

It would then be appropriate to propose that underlying biological conditions, which are unique to males or females, could have caused the distinction in their spatial abilities. This proposition had been corroborated by findings of Hooven et al. (2004), which illustrated that higher testosterone levels in males was likely to have enhanced their spatial task performance. Findings of Hausmann et al. (2000) also attributed higher estrogen and progesterone levels in their midluteal phase to their poorer performance in spatial tasks. In addition, fundamental environment factors, such as “masculine gender-typed activities” could have also contributed to better spatial ability in males, as demonstrated in the results of Casey and Brabeck’s (1990) study.

Nevertheless, limitations to the present study could have undermined its results. While mental rotation is a possible measure of spatial ability in both genders, it is not absolute. There exist other components of spatial ability, namely spatial perception and spatial visualization (Rileaa, Roskos-Ewoldsenb & Bolesb, 2004), which could yield different results from that of mental rotation when performed and measured. Furthermore, as noted by Collins and Kimura (1997), it is uncertain whether the superior performance in the three-dimensional Mental Rotations Task by males is associated with the nature of that particular task or its higher level of difficulty relative to other rotation tasks in general. This threatens the construct validity of the study.

Perhaps considerations for future studies could include the measurement of spatial perception and spatial visualization, such as water level and paper folding, as utilized in the study by Rileaa et al. (2004), so as to obtain a more complete measure of spatial ability. Additionally, other types of mental rotation tasks, such as the two-dimensional picture rotation used by Collins and Kimura (1997), could also be included to ensure that the better performance by males is explainable in various mental rotations tasks, and not limited to the three-dimensional ones only.

References

Casey, M. Beth & Brabeck, Mary M. (1990). Women Who Excel on a Spatial Task: Proposed Genetic and Environmental Factors. Brain and Cognition, 12, 73-84.

Collins, David W., Kimura, Doreen. (1997). A Large Sex Difference on a Two-Dimensional Mental Rotation Task. Behavioral Neuroscience, 111, 845-849.

Hausmann, Markus, Sabbekoorn, Ditte, Van Goozen, Stephanie H. M. & Cohen-Kettenis, Peggy T. (2000). Sex Hormones Affect Spatial Abilities During the Menstrual Cycle. Behavioral Neuroscience, 114, 1245-1250.

Hooven, Carole K., Chabris, Christopher F, Ellison, Peter T. & Kosslyn, Stephen M. (2004). The Relationship of Male Testosterone to Components of Mental Rotation. Neuropsychologia, 42, 782-790.

Rilea, Stacy L., Roskos-Ewoldsenb, Beverly & Bolesb, David. (2004). Sex differences in spatial ability: A lateralization of function approach. Brain and Cognition, 56, 332-343.

Roberts, Jonathan E. & Bell, Martha Ann. (2000). Sex Differences on a Mental Rotation Task: Variations in Electroencephalogram Hemispheric Activation Between Children and College Students. Developmental Neuropsychology, 17, 199-223.

Vandenberg, S. & Kuse, A.R. (1978). Mental Rotations: A group test of three-dimensional spatial visualization. Perceptual and Motor Skills, 47, 599-604.