BIOLOGICAL DIFFERENCES BETWEEN GENDERS: HORMONES AND NERVOUS SYSTEM

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Gender Issues In Psychology (PSY - 512)

Lesson 08

BIOLOGICAL DIFFERENCES BETWEEN GENDERS: HORMONES AND NERVOUS

SYSTEM

Hormonal Abnormalities:

Adrenogenital Syndrome

Excessive prenatal production of androgen from adrenal glands causes this syndrome. In male fetus it doesn't

cause major problems. But in female fetus this results in birth of female with physical structure resembling

boys. Increased androgen levels not only affect physical characteristics behavior is also affected. Sometimes

surgeons recommend surgery for correction of external genitalia. This syndrome also influence play activities of

girl child. Berenbaum & Snyder, (1995) stated that girls with such syndrome are more likely to be "tomboys".

Androgen Insensitivity Syndrome:

Found in normal XY male fetus with body cells insensitive to androgens.

Cause: abnormal functioning of androgen receptors

Individuals with this syndrome have XY chromosomal structure.

But inability of androgen receptors does not allow the proper development masculine characteristics. At the

same time they have internal male reproductive organs as the Mullerian- inhibiting substance is present.

Inability of androgen receptors does not allow the proper development of male reproductive structures, that

requires a degeneration of the Mullerian system and the development of Wolffian system.

Such babies appear to be girls at the time of birth. Such individuals have been found to have gender identity,

behavior and appearance of females (Hines, Ahmed & Hughes, 2003).

Sex Differentiation in Nervous System:

Men and women differ not only in their physical attributes and reproductive function but also in many other

characteristics, including the way they solve intellectual problems. Studies reflect that the effect of sex

hormones on brain organization starts parentally. Sex differentiation of human brain is mostly dependent on

the prenatal exposure to androgen (testosterone). First gender difference exists in size of the brain. Males have

larger brain size than females. The area in the brain that regulates female and male reproductive behavior is the

hypothalamus. This tiny structure at the base of the brain connects to the pituitary, the master endocrine gland.

It has been shown that a region of the hypothalamus is visibly larger in male rats than in females and that this

size difference is under hormonal control.

Researches have shown that men's left side of brain is more developed that is responsible for conventionally

logical thought, abstract and analytic thinking. Women's right side of brain is more developed that is

responsible for imaginative, artistic activity, holistic & intuitive thinking, visual and spatial tasks. Studies have

also revealed that women have superiority on tasks needed memory. These differences can be revealed form

following studies examples:

Average men perform better than women at certain spatial tasks. They also outperform women in

mathematical reasoning tests. Men exhibit more accuracy in tests of target-directed motor skills.

Average women excel on tests that measure recall of words and on tests that challenge the person to find

words that begin with a specific. They also tend to be better than men at rapidly identifying matching items and

performing certain precision manual tasks, such as placing pegs in designated holes on a board etc.

The Psychological Perspectives about Gender Development and Gender Differences

Gender development refers to the process of identifying oneself as being male or female, and

gender roles are expected, and set, thinking and behavior patterns for males and females.

Theories of Gender Development:

Psychological theories that study, describe, understand, explain, and predict the development of gender roles,

stereotypes, gender differentiation and other related issues.

Nature and Nurture

Gender Issues In Psychology (PSY - 512)

Nature: Refers to hereditary influences, and nurture means environmental influences.

Both influences are essential and are mutually influential. For example children's response to parenting an

(environmental influence) is determined by children's temperament and other inherited characteristics e.g.,

physical condition. Development and expression of hereditary characteristics is also affected by environmental

influences. In the last century there have been significant increases in average height because of improved

nutrition and medical care, in spite of the fact the height is a strongly inherited characteristic.

So, is it nature that influences nurture, or is it nurture that modifies nature?

Psychologists have tried to explain the phenomenon of gender differences according to their respective

theoretical approaches.

There are at least eight different theories in psychology that explain gender development:

1. The Biological Approach

2. The Behavior Approach

3. Observational Learning Approach

4. The Cognition Approach

5. The Psychoanalytic Approach

6. Humanistic Approach

7. The Socio cultural Approach

8. The Epigenetic Approach

The Biological Approach:

Emphasizes on biological processes and constitution that cause physical differences between men and

women. Males and females have different sets of chromosomal make up. Human beings have 23 pairs of

chromosomes. The 23rd pair of chromosomes is called sex chromosomes: in females it is XX and in males

it is XY. Therefore men and women are born with different genetic patterns.

How this genetic pattern will express itself will depend upon the action of hormones. Certain hormones

affect the development of physical sex characteristics. According to biological theory differences in

chromosomes (X/Y) and hormones (testosterone/estrogen) determine the behavioral differences between

boys and girls. Androgen hormones are related to male characteristics. The most important androgen is

testosterone. The androgens have a very vital role in determining prenatal physical development. The

absence of androgens means the fetus will develop female characteristics and the absence means the fetus

will develop male characteristics

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