Sex And Laterality Essay, Research Paper

Abstract

This paper discusses the differences in laterality among males and females. More specifically, it discusses the differences in verbal and visuospatial ability among different sexes. The common hypothesis, which has been proven by various people, is that males are superior to women in visuospatial tasks while women are superior in verbal tasks. This difference among males and females is due to the fact that the male brain is more lateralized than that of a female. The purpose of the experiment explained in this paper was to prove the common hypothesis by testing males and females with a verbal and visuospatial task.

"Laterality refers to the preferential use or superior function of one part of the body?" (Martin, 1998, p.135) Laterality pertains to the idea that certain functions or tasks can be performed better by one side of the body. Specific to this paper, certain parts of the brain are designated to perform only certain tasks. It has been proven that the brain is lateralized, meaning that one hemisphere is dominant for specific functions and the other is dominant for other functions. "The conventional view of hemispheric function is that the left hemisphere is rational, verbal, linear, and analytical whereas the right hemisphere is emotional, spatial, holistic and intuitive." (Martin, 1998, p.140) Though the right brain is more involved in aspects of visuospatiality and the left more involved in language ”?the right hemisphere is capable of undertaking rudimentary or compensatory language processing and the left hemisphere is capable of undertaking some spatial processing."(Martin, 1998, p.140)

The idea of lateralization can be applied to the difference among people in handedness. It has been observed that left-handed people appear to be superior to right- handed people on tests of verbal skills. However, left handers are inferior to right handers on tests of visuospatial tasks. The reason that left-handed people have superior verbal ability is because they have more mass of the left brain able to be devoted to language. Therefore, since there is a large area of the right hemisphere devoted to language little mass is available to visuospatiality, its own specialization. (Springer & Deutch, 1981, p.154) Handedness is one of many ways in which the presence of laterality in the brain can be observed.

Through various studies it has been found that the female brain is less lateralized than the male brain. A great amount of evidence has shown that females are superior to males in tasks, which involve the use of language while males are superior to females in spatial tasks. (Springer & Deutch, 1981, p.121) It is found that the female brain is more symmetrical than the male brain. This means that there is less neural mass in the female brain to devote to specific functions. Males are able to devote a large amount of their left brain to verbal tasks and a large amount of their right brain to visuospatial tasks. However, this means that if one section of the brain is damaged a male may totally lose ability to perform the tasks associated with that part of the brain. But, because the female brain is more symmetrical, damage to a section of the brain may not be inhibited because an identical section may be present on the opposite side of the brain. The left hemisphere of the female brain is still mostly devoted to language but the right hemisphere is not devoted to visuospatial tasks as much as the male brain.

Because of the information discussed above it is hypothesized that the results of this experiment will reveal a difference between males and females. It is expected that the males will perform better on the visuospatial task and the females will perform better on the verbal task.

The tasks used in this experiment are considered pure tasks, meaning that only either visuospatiality or verbal ability was tested. In an impure task both abilities are tested. If the two abilities are tested together than the results will not be accurate. (Coltheart, Hull & Slater, 1975, p. 439)

Method

This experiment involved 97 psychology students; 27 males, 70 females. The materials used in this experiment consisted of a pencil/pen, a stopwatch, and paper.

The instructor must separate the students into groups of two. For the first task one person was the recorder and the other was the subject being experimented on. The groups were arranged so that an even number of males and females participate in each task.

The first task required the students to mentally go through the alphabet, A to Z and count the number of letters which contain the sound ‘ee’. This is only a mental task. Nothing was to be used by the student being tested to aid them. The instructor told the students when to begin. When instructed the recorder started the stopwatch immediately and the subject began the task. When the subject was completed the task the recorder recorded the time needed to complete the task. The results were then handed into the instructor to compile the results.

For the second task the recorder and subject reversed roles. This task required the subject to mentally go through the alphabet, A to Z, and count the number of letters which contain a curve in the typed, capital form of the letter. The subject was timed and the results were recorded and handed into the instructor.

Results

From the first task the overall mean was a time of 21.71 seconds and an answer of 8.60. The mean answer for the females was 9.38 with a time of 19.66 seconds as compared to the males with a mean answer of 7.87 and a time of 23.75 seconds. The correct answer for this task was 9 letters containing the sound ‘ee’. This answer was obtained only if the letter ‘Z’ was pronounced ‘zee’ not ‘zed’.

From the second task the overall mean was a time of 27.76 seconds and an answer of 11.46. The mean answer for females was 12.03 with a time of 29.81 seconds as compared to the males with a mean answer of 11.06 and a time of 25.92 seconds. The correct answer for this task was 11 letters containing a curve in the typed, capital form.

Discussion

From the results obtained from the experiment the hypothesis that males are superior to females in visuospatial tasks and that females are superior to males in verbal tasks has been proven to be true. The first task was a verbal task as it involved the pronunciation of words which is associated with language. The results obtained from the verbal task revealed that the females were able to complete the task quicker and more accurately than the males. This supports the fact that "?females are superior to males in a wide range of skills that require the use of language?" (Springer & Deutch, 1981, p.121). However, the results from this task are somewhat inaccurate because it was not specified whether the letter ‘Z’ was to be pronounced as ‘zee’ or ‘zed’. Because of this inaccuracy, the results of the first task can not be truly analyzed to explain the differences in verbal skills.

The results obtained from the second, visuospatial task support the belief that males are able to perform better on spatial tasks. The males were able to complete this task quicker and more accurately than the females. These results support the ideas discussed in the literature.

The difference in laterality between males and females has been observed but, what is the reason for these differences? It has been suggested that because females tend to be weaker than males a greater ability to vocalize is needed for a means of protection. (Geschwind and Galaburda, 1984, p.138) In addition, it is believed that throughout evolution males have been the hunters and so require good visuospatial skills in order to be successful. Whereas the women have been the mothers and so have a greater need for the use of communication. (Springer & Deutch, 1981, p. 128)

Coltheart, M., Hull, E. & Slater, D. (1975). Nature ( Volume 253), pp.438 – 440.

Geschwind & Galaburda. (1984). Cerebral Dominance,U.S.A: President and Fellows of Harvard College.

Martin, G. (1998). Human Neuropsychology. Middlesex: Prentice Hall Europe.

Springer, S.P., & Deutch, G. (