70) Often not noticed as retarded by casual observer. Can acquire practical skills and useful reading and arithmetic to sixth-grade level. Can usually achieve social and vocational skills necessary for self maintenance but is slower to walk, feed self, and talk than most children . Can be guided toward social adjustment. May need occasional guidance and support when under unusual social or economic stress.
MODERATE (IQ 36-50) Noticeable delay in motor especially in speech; responds to training in various self-help activities. development,Can learn simple communication, Can perform simple tasks under elementary health and safety habits, and sheltered conditions; participates in simple manual skills; does not progress simple recreation; travels alone in familiar places; usually incapable of self-maintenance.
SEVERE RETARDATION (IQ 20-35) Marked delay in motor development; little or no communication skill; may respond to training in elementary self-help -- for example, self-feeding. Usually walks, barring specific disability;has some understanding of speech and ' some response; can profit from systematic habit training Can conform to daily routines and repetitive activities; needs continuing direction and supervision in protective environment.-
PROFOUND RETARDATION (IQ below 20) Gross retardation; minimal capacity for functioning in sensorimotor areas; needs May walk, Obvious delays in all areas of development; shows basic emotional responses; may respond to skillful training in use of legs, hands, and jaws; needs close supervision May walk, need nursing care, have primitive speech, usually benefits from regular physical activity. ; incapable of self-maintenance
Mental retardation has many causes. Some are genetic accidents, such as Mongolism or Down's syndrome, which are caused by an extra chromosome. Some are caused by physiological problems, such as cretinism, which results from thyroid deficiency. Some are due to physical factors such as not receiving enough oxygen before birth. And many are simply a combination of hereditary and environmental factors; the parents were retarded and did not provide a stimulating home environment for the children.
INTELLIGENCE DIFFERENCES BETWEEN GROUPS
Gender differences In these days of an increased sexual equality across many activities, the question arises: "Are women as intelligent as men?" The answer is unclear. The sexes differ in specific abilities. Females are typically superior in verbal abilities and in items concerned with social relations. They also perceive details more quickly and accurately and do better on tests of memory. Males, on the other hand, surpass women on items that involve spatial, numerical, and mechanical performance. These differences, however, are averages. The variance within each sex is much greater than the difference in results between the sexes. In scores of overall intelligence, the two sexes seem to be about equal. All differences are restricted to specific abilities, not to the composite that we call intelligence. It is debatable, however, whether the differences in specific abilities are due to biological or cultural factors.
A recent study by Stumpf and Stanley (1999) investigating gender differences in scholastic achievement, suggests that the historic differences between the sexes may not be decreasing as much as earlier suspected. They examined the performance of over eight hundred thousand test takers on the College Board Advanced Placement (AP) tests and the College Board Scholastic Assessment Test (SAT). They found that males showed advantages mainly in Physics, Computer Science, Chemistry and Calculus; but also in Economics, Government, U.S. History and Biology. Females showed advantages in Spanish and French Literature, English Literature, and Art History. This pattern remained relatively stable over the period of the study, from 1984 to 1996, even though the subjects changed. There has been a decline, however, in the advantages which males show in Computer Science. The AP tests were half multiple-choice and half open-ended items, compared