Biological Differences Between Genders Lecture

Biological differences between genders introduction  Biological differences between males and females are found in three ways:  In chromosomes  In hormones  In structure of the nervous system Sexual Differentiation and role of Chromosomes:  Sexual dimorphism: is existence of two se...

Biological differences between genders introduction  Biological differences between males and females are found in three ways:  In chromosomes  In hormones  In structure of the nervous system Sexual Differentiation and role of Chromosomes:  Sexual dimorphism: is existence of two sexes (male & female) in a species, including differences in genetics, gonads, hormones, internal genitalia and external genitalia. Sex Chromosomal Abnormalities:  Female Sex Chromosome Abnormalities:  Turner’s syndrome  Metafemales or triple-X females  Male Sex Chromosome Abnormalities:  Klinefelter syndrome:  XYY syndrome: Female Sex Chromosome Abnormalities Turner’s syndrome:  This syndrome occurs when individual inherit only one X chromosome and their sex chromosomal structure is XO.  Such cases are females in sex with abnormal growth patterns. They are short in stature, averaging 4 foot 7 inches as adults, and often have distinctive webbed necks (i.e., extra folds of skin), small jaws, and high arched palates.  They generally lack prominent female reproduction ability. They have exceptionally small, widely spaced breasts, broad shield-shaped chests, and turned-out elbows. Their ovaries do not develop normally and they do not ovulate. conti...  If diagnosed in early childhood, regular injections of human growth hormones can increase their stature by a few inches.  Beginning around the normal age of puberty, estrogen replacement therapy can result in some breast development and menstruation.  These treatments allow Turner’s syndrome women to appear relatively normal. conti... Metafemales or triple-X females:  Such females inherit three X chromosomes.  Their chromosomal structure is XXX. As adults, these "super-females" are usually an inch or so taller than average with unusually long body structure.  They have normal development of sexual characteristics and are fertile.  They may have slight learning difficulties and are usually in the low range of normal intelligence.  They tend to be emotionally immature for their size during childhood. This type of chromosomal abnormality is less rare than Turner syndrome. Male Sex Chromosome Abnormalities Klinefelter syndrome:  Individual with this syndrome inherit on extra X chromosome and their chromosomal structure is XXY.  They characteristically have relatively high-pitched voices, feminine body contours as well as breast enlargement, and comparatively little facial and body hair. conti... XYY syndrome:  The individual with this abnormality receive extra Y chromosome and their chromosomal structure is XYY.  As adults, these "super-males" are usually tall (above 6 feet) and generally appear and act normal. However, they produce high levels of testosterone.  During adolescence, they often are slim, have severe facial acne, and are poorly coordinated. They are usually fertile and lead ordinary lives as adults. Majority remain unaware that they have a chromosomal abnormality. 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”. conti... 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.  Inability of androgen receptors does not allow the proper development of male reproductive structures. 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. conti...  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: conti...  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. CH # 3  Do men have greater spatial and math abilities than women?  Do women have greater verbal skills than men? Spatial skills involve the ability to think about and reason using mental pictures rather than words. E.g., reading maps, doing jigsaw puzzles, finding where you put your keys (diversity of tasks). Men are consistently better than women in their accuracy at hitting a target. Men outperform women in “mental rotation” Men use what has been called a leaping strategy (men find the two matching stimuli and then move on to the next item). whereas women use a conservative strategy (examine all four stimuli to ensure that they have found the correct matches which takes more time).  Women outperform men on both (object identity and object location With object identity memory, the experimenter presents the respondent with a set of objects, such as those shown in Figure 4.6a, removes them, and then presents a new set of objects, some of which are old and some of which are new, as shown in Figure 4.6b. The task of the respondent is to identify which objects are old and which are new.  For object location memory, the objects are not changed but their location is moved, as shown in Figure 4.6c. Here the task of the respondent is to identify which objects have been moved. Women outperformed men when objects were feminine or neutral, but men outperformed women when objects were masculine. There is a paradox when it comes to gender and math. Males perform better than females on math achievement tests, such as the SAT, but females receive better math grades in school Girls have a more mastery-oriented style (I do math to improve my skills), whereas boys have a more performance-oriented style (I do math to show my teacher I’m smarter than the other students). e.g., females outperformed males on essay writing. feeling the same emotion as another person or feeling sympathy or compassion for another person. Sex differences in empathy, like sex differences in cognition, depend on how empathy is measured. The sex difference was greater when empathy was measured by self-report than by observation. When measures that were less under the conscious control of the participant were used, such as parent/teacher observations, sex differences appeared in the same direction but of a much smaller magnitude. One concern with self-report measures is demand characteristics. Undoubtedly, men and women realize that women are supposed to be more empathetic than men. Thus women and men may distort their self-reports of behavior in the direction of gender-role norms.  Men are more likely than women to help in situations of danger or emergencies, but that women are more likely than men to help within the context of relationships (Dovidio & Penner, 2001) and in nonthreatening situations such as volunteering (U.S. Department of Labor, 2009a).  Thus, women and men are more likely to help in situations congruent with their gender roles. Women’s help is communal (caring for an individual), and men’s help is agentic (caring to gain status, heroic helping, Eagly, 2009).  A meta-analytic review of sex comparisons showed that men were more aggressive than women (Bettencourt & Miller,1996). There were no sex differences in verbal aggression in the fieldBettencourt & Miller, 1996). When more indirect forms of aggression, such as relational aggression, are examined, sex differences may disappear One important situational factor is provocation. The Bettencourt and Miller (1996) meta-analysis showed that provocation led to greater aggression than nonprovocation, and that provocation altered the size of the sex difference in aggression. The sex difference was smaller under provocation conditions.  Measuring aggression is not as easy as you might think. The limitations of self- report methods are obvious. Are observations of behavior any more objective? same behavior may be construed differently when it is observed in a man or a woman. We may have a lower threshold for labeling a behavior as aggressive when the perpetrator is female compared to male. Sex differences in personality also may be more strongly linked to gender roles rather than sex. For example, empathy is associated with being female and with psychological femininity, or communion. The sex difference in empathy is completely accounted for by empathy’s association with communion (Karniol et al., 1998). men and women are viewed as behaving differently due to their distinct social roles; no personality traits are inferred from behavior. Gilligan (1982) argued that women have a morality of responsibility that emphasizes their connection to others (according to Kohlberg conventional stage), whereas men have a morality of rights that emphasizes their separation from others (according to Kohlberg post conventional stage). As, (Jaffe & Hyde, 2000) study also showed that Women scored higher than men on a care orientation and men scored higher than women on a justice orientation. The problem with previous theories of social development is that the sequence of establishing an identity before achieving intimacy may describe men’s experiences more than women’s.  (1) there are few sizable sex differences  (2) among the ones that do exist, there is a host of moderator variables.