DIFFERENCES IN VISUAL AND SPATIAL ABILITY BETWEEN GENDERS
To: Dr. Peuchaud
By: Scott P. Fladland
Nov 1, 2010
Abstract:
Our class and two others participated in a lab experiment called the Mental Rotation Test (MRT). The experiment was conducted to determine weather there is a significant difference in visual and spatial abilities between genders. The MRT tested our ability to find the single matching shape among four similar shapes. Our class was the only one in which the men’s average was lower than that of the women. Nevertheless our male average score of 22 correct was still right at the overall MRT male average. The women in our class however, scored higher than the overall MRT female average. The overall score average for all three classes (men 24, women 20) still resulted in the same conclusion from past years, which is that men score higher on the MRT experiment.
Table of Contents:
Introduction, Theoretical principles, Methods, Results, Figure #1 and Figure #2, Discussion of results, Conclusions and Recommendations, References. MRT = Mental Rotation Test.
Introduction:
The purpose of our experiment is to determine weather there is a significant difference in visual and spatial ability between genders. Our Lab experiment used the timed MRT to test male and female visual and spatial abilities. The over all result s of our three classes were consistent with the results of previous years. However my class was an anomaly because the women outscored the men. The women in our three classes also scored slightly above the average score that women usually get on the MRT and the men scored a little below their normal average.
Extensive reports have been done that show a male advantage for a variety of spatial ability tasks. From early adolescence through adulthood gender differences in visual and spatial
ability has been evident. There is conflicting evidence for gender differences in early grade school children though, probably because they haven’t had enough time to develop. Our instructor did an excellent job having us take the MRT without giving away what it tested and why we were taking it. Although I suspected we were taking the test for our lab paper I didn’t know what we were testing for. If I’d known I probably would have rushed to complete it and wouldn’t have done as well as I did, even though I scored well below average anyway.
Theoretical Principles:
To come up with our individual scores on the MRT we had to subtract ½ of the number wrong from the number right to correct for guessing. Then calculate the corrected total score for parts one and two, separately and together. My individual score was only a 12; thankfully most of the other men in our class did better.
In determining our total class average for all three classes we used this equation: Average male score minus average female score/ divided by average male score plus average female score. Our three class overall men’s average was 983/41= 23.97 which we rounded up to 24. The women’s average was 362/18= 20.11 which we rounded to 20.
In a 2008 study paid for by the National Science Foundation in the United States, researchers found that "girls perform as well as boys on standardized math tests. Although 20 years ago, high school boys performed better than girls in math, the researchers found that is no longer the case. The reason, they said, is simple: Girls used to take fewer advanced math courses than boys, but now they are taking just as many." However, the study indicated that, while on average boys and girls performed similarly, boys were overrepresented among the very best performers as well as among the very worst. Studies have also shown that boys and girls tend to
differ in the variance of their ability, though which gender shows the greatest variance tends to differ between countries; in some countries, such as the Netherlands, girls tend to have a greater variance than boys, whereas in others, such as the US, boys have the greater variance.
Spatial abilities: large differences favoring males are found in performance on visual-spatial tasks (e.g. mental rotation) and spatio-temporal tasks (e.g. tracking a moving object through space). The male advantage in visual-spatial tasks is approximately one standard deviation, and becomes experimentally discernible at puberty. A minority of opinions are known to differ on this issue: In his book, Developmental Influences on Adult Intelligence: The Seattle Longitudinal Study, K. Warner Schaie concludes that there are few sex differences in spatial competencies.
Memory: Women show greater proficiency and reliance on distinctive landmarks for navigation while males rely on an overall mental map. Studies by H. Stumpf and Richard Lynn have also demonstrated statistically significant medium- and short-term memory advantages in women. A study examining sex differences in performance on the California Verbal Learning Test found that males performed better on Digit Span Backwards and on reaction time, while females were better on short-term memory recall and Symbol-Digit Modalities Test.
In the nineteenth century, whether men and women had equal intelligence was seen by many as a prerequisite for the granting of suffrage. Leta Hollingworth argues that women were not permitted to realize their full potential, as they were confined to the roles of child-rearing and housekeeping. From the late twentieth century onwards, sex differences in intelligence have been discussed to determine whether disproportionate employment or payment favoring men is a manifestation of sexism or simply a reflection of innate aptitudes.
In 1861, Paul Broca examined 432 human brains and found that the brains of males had an average weight of 1,325 grams, while the brains of females had an average weight of 1,144 grams. Other differences that have been established include greater length in men of myelinated axons in their white matter (176,000 km compared to 146,000 km); and 33% more synapses per mm3 of cerebral cortex.
In studies concerning intelligence, it has been suggested that the ratio of brain weight to body weight is more predictive of IQ levels, rather than actual brain weight. While men's brains are an average of 10-15% larger and heavier than women's brains, some researchers propose that the ratio of brain to body size does not differ between the sexes. However, some argue that since brain-to-body-size ratios tend to decrease as body size increases, a sex difference in brain-weight ratios still exists between men and women of the same size. A 1992 study of 6,325 Army personnel found that men's brains had an average volume of 1442 cm³, while the women averaged 1332 cm³. These differences were shown to be smaller but to persist even when adjusted for body size measured as body height or body surface, such that women averaged 100g less brain mass than men of equal size.
An alternative proposal is the measurement of gray matter or white matter volume in the brain as an indicator of intelligence; the former used for information processing, whereas the latter consisting of the connections between processing centers. Neuroimaging studies, such as MRI and CT, have demonstrated loss of gray matter volume in conditions associated with cognitive impairment, such as Alzheimer's disease, front temporal dementia and senile dementia. In 2005, Haier et al. reported that, compared with men, women show more white matter and fewer gray matter areas related to intelligence. Using brain mapping, it was shown that men have
more than six times the amount of gray matter related to general intelligence than women, and women have nearly ten times the amount of white matter related to intelligence than men. They also report that the brain areas correlated with IQ differ between the sexes. In short, men and women apparently achieve similar IQ results with different brain regions.
Despite these findings, there still remains no clear relationship between physical brain measurement and functional capacity. Some have suggested that physical studies of the brain in predicting intelligence are largely arbitrary due to the inherent neuroplasticity of the organ and the multitude of ways that brain function can be influenced by the stimulating quality of the environment and hormonal influences.
The importance of testosterone and other androgens as a cause of sex differences has been a subject of study. Adult women who were exposed to unusually high levels of androgens in the womb due to a condition called congenital adrenal hyperplasia score significantly higher on tests of spatial ability. Girls with this condition play more with "boys' toys" and less with "girls' toys" than unaffected controls. Many studies find positive correlations between testosterone levels in normal males and measures of spatial ability. However, the relationship is complex.
It is possible that sexual dimorphism may exist in regard to intellectual abilities in humans. Men may have evolved greater spatial abilities, possibly as a result of certain behaviors, such as navigating during a hunt that they were more likely to be involved in during humans' evolutionary history. Similarly, women may have evolved to devote more mental resources to gathering food, as well as understanding and tracking relationships and reading others' emotional states in order for them to be able to better understand their social situation.
Another possibility is the effects of socialization. Girls are sometimes discouraged from studying math or science. Similarly, boys are sometimes discouraged from displaying empathy, or from spending much time reading for pleasure.
Methods:
The MRT tested our ability to look at a drawing of a given object and find the same object within a set of dissimilar objects. The only difference between the original object and the chosen object was that they were presented at different angles.
The MRT has two parts. Our instructor gave us three minutes for each of the two parts. Each part had two pages. When we finished part one or as in my case when the time was up we stopped. We were not allowed to go to part two until our instructor told us to.
The instructions that I neglected to read also said; Work as quickly as you can without sacrificing accuracy. Your score on this test will reflect both the correct and incorrect responses. Therefore, it will not be to your advantage to guess unless you have some idea which choice is correct.
Mental rotation is the ability to rotate mental representations of two-dimensional and three-dimensional objects. Mental rotation is somewhat localized to the right cerebral hemisphere. It is thought to take place largely in the same areas as perception. It is associated with the rate of spatial processing and intelligence.
In a mental rotation test, the subject is asked to compare four 3D objects (or letters) and state if they are the same image or if they are mirror images (enantiomorphs). Commonly, the test will have pairs of images each rotated a specific amount of degrees (eg. 0º, 60º, 120º or 180º). Some pairs will be the same image rotated, and others will be mirrored. The subject will be
shown a set number of the pairs. The subject will be judged on how accurately and rapidly they can distinguish between the mirrored and non-mirrored pairs.
Roger Shepard and Jacqueline Metzler originally discovered this phenomenon. Their research showed that the reaction time for participants to decide if the pair of items matched or not was linearly proportional to the angle of rotation from the original position. That is, the more an object has been rotated from the original, the longer it takes an individual to determine if the 2 images are of the same object or enantiomorphs.
In further research, Shepard and Cooper have proposed the concept of a "Mental Imagery" facility, which is responsible for the ability to mentally rotate visual forms. Additionally, it has been found it does not matter on which axis an object is rotated, but rather the degree to which it is rotated that has the most significant effect on response time. So rotations within the depth plane (i.e., 2D rotations) and rotations in depth (3D rotations) behave similarly. Thus, the matching requires more time as the amount of depth rotation increases, just as for within the depth plane.
Results:
Our class was the anomaly since our women’s average was higher than our men’s. The females in our class scored a 98/4= 25 MRT answers correct average, while our men scored a 379/17= 22 correct average. We had 17 men and only four females in our class. To come up with these results we divided total amount of correct MRT test answers by the number of people in that gender.
The results for the three class averages combined in 2010 was; 983/41=24 for the males, and 362/18=20 for the females.
Figure #1
Figure 1: Examples of pairs of objects presented in the experiment by Shepard and Metzler (1971) that differ by a rotation in the picture plane (A), by a rotation in depth (B), or that are intrinsically different (specifically, enantiomorphic) in shape (C).
Figure #2 Average scores between men and Women.
Discussion of Results:
Our results were pretty close to the average scores of the past, but our men scored lower than every average except that of 1996. Our women scored a higher average except the one from 2001. So I think it’s safe to say our males didn’t do as well as expected and our women did better than expected.
There may have been some errors in the experiment that could have affected the outcome. Some people may have cheated by saying they had a better score than they really did. Some people may have done the equations incorrectly which would produce an incorrect score. Others may not have figured out how to get the score total correct when circling the number of correct
answers or crossing out the wrong ones. Of course this is all just speculation it’s possible everyone followed the directions perfectly and honestly. The only obvious error is the disproportionate ratio of men (41) to women (18).
However as Dale Jacobson and I discussed in class we decided everything besides the ratio difference probably didn’t effect the over all results very much. I used myself as an example by showing that even if I had scored a 40 instead of a 12, our male class average would have been virtually unchanged. We would still have the same average when rounded to the nearest whole number.
Conclusion:
With this MRT lab experiment we helped prove is a difference in visual and spatial abilities between genders, although this time in wasn’t a significant one. There was only a four point differential in our overall averages and the females in my class did better than the men. I’m pretty sure that my verbal abilities are better than my visual and spatial aptitude. I’ve always done very well in English but poor in Math, which may explain my low score on the MRT. Overall I think this experiment was a success because the results were similar to those of the past and everyone participated willingly.
References:
Smythe, K. (2008). Thinking Differently: Differences Between Men and Women. New York: Wiley.
Bannon, M.E. (2004). The two sexes: Growing up apart, coming together. Cambridge, MA: Belknap Press.
University Of Toronto (2004, August 5). Study Explains Spatial Orientation Differences Between Sexes; Inner Ear Size May Be Determinant. ScienceDaily. Retrieved May 3, 2010, from http://www.sciencedaily.com /releases/2004/08/040805091122.htm.
Appendix:
Our class average scores; Men 397/17=22, Women 98/4=25.
Three class averages combined; Men 983/41=24, Women 362/18=20.
mm3 = millimeters cubed. cm3 = centimeters cubed.
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