©Arlene Taylor PhD

Although the male brain is generally larger than the female brain, absolute brain size appears to have little to do with intelligence. Scientists have found that the brains of mentally challenged individuals were sometimes larger than those of geniuses. For another, many different “types” of intelligences have been identified (e.g., emotional, intellectual, mathematical, musical, linguistic, spatial). It is difficult to test for, or to assess these differing types of intelligences, especially since most of our traditional methods of assessment involve words and some types of intelligences are not easily assessed by means of verbal skills.

Although IQ testing is falling into disfavor?or at least is not being relied upon to the degree it has been in the past, as a valid or infallible measure, and rightly so?there are some interesting observations about past samplings of IQ scores. For example, large sample testing shows no difference in averaged overall IQ scores based on gender. This has presented a paradox in terms of towering geniuses—most of which have been male.

A factor in this puzzle may be the difference in lateralization. The male brain may function like a pair of specialists; the female brain like a generalist. There is some evidence that IQ scores can be raised 10-15 points depending on the way in which an individual’s brain is nurtured, stimulated, and challenged, which can further complicate the process of drawing conclusions about “intelligence” through the use of traditional IQ testing.

Female Brains

Male Brains

• IQ test section scores tend to be higher in areas that require language fluency (e.g., synonyms, homonyms). In the USA a female holds the highest recorded IQ score.

• There doesn’t appear to be any relationship between IQ scores and career accomplishment in females. In one study, two thirds of women with genius IQ levels of 170 or above were housewives or office workers.

• Tend to achieve higher IQ scores in test situations when the environment is quiet and free from distraction. This may reflect the more generalized style of processing and an increased sensitivity to sounds.

• IQ test section scores are often higher in areas that require mathematical and/or spatial reasoning. In test situations, males tend to achieve higher scores when there is some distraction in the environment.

• There is a close relationship between IQ scores and career accomplishment. Males with high IQ scores are usually high achievers.

• Tend to achieve higher IQ scores in test situations when there is some noise or distraction in the environment. This may reflect the more lateralized style of processing and a more focused orientation toward setting and achieving goals.

Although overall scores average out equally, the type of intelligence and section scores differ by gender. Males tend to score higher on sections that require the use of visual-spatial ability while females excel on sections that assess vocabulary and word usage.

When IQ scores are plotted across the bell curve of distribution, another gender difference can be identified. IQ scores for females are distributed quite evenly across the bell curve of distribution while scores for males are distributed more heavily at either end. This means that there are more males (than females) in institutions for the mentally challenged; there are also more male towering geniuses in the fields of art, literature, and music.

IQ and Birth Order

There appears to be a relationship between sex hormone levels at birth and the IQ of the eldest child. One study showed that if the firstborn is a boy and several years have elapsed before the birth of a second son, the hormone levels in the mother seem to bounce back and the younger brother may have the advantage of the same rich hormonal mix as the firstborn. The girl that follows a firstborn boy, however, will not have the benefit of the higher hormonal mix. If the firstborn is female there doesn’t seem to be such a definite dip in hormones for the second child. Therefore, there may be some argument for having a girl first and then a boy several years later. Interestingly enough however, some studies show that both males and females hope their first child will be a boy.



• Because their left hemisphere matures first, females can excel in elementary school classes because many activities are geared to left hemisphere learning.

• Females are more likely to develop math anxiety and may have more difficulty with subjects such as geometry, trigonometry, chemistry, biology, and physics.

• Their right hemisphere may take twice as long to develop as it does for comparable males. About 25% of females do well in spatial tests.

• Females tend to breathe more frequently but less deeply at each inspiration. Shallower breathing may be a factor in the amount of damage resulting from lead poisoning due to exhaust fumes.

• The right cerebral hemisphere is more developed at birth and becomes more specialized by the age of six. Males may be at a disadvantage in the typical elementary school because of an emphasis on left hemisphere subjects.

• Males often excel in right hemisphere subjects (e.g., geometry, trigonometry, chemistry, biology, physics) if they are still in school by the high school years.

• Males tend to be superior at tasks involving spatial ability. About 75% do well in spatial tests.

• Males tend to breathe less often but more deeply at each inspiration. This may place them at higher risk when undergoing general anesthetics. It may also place boys at higher risk for breathing in toxic fumes. For example, boys scored lower than girls in studies of children with high concentrations of lead in their bodies.

Studies reported recently in the British Medical Journal, Lancet, indicate that females likely obtain their IQ genes (cross-linked) from their father. Males likely obtain their IQ genes (cross-linked) from their mother. Multiple intelligences, so called, (e. g, verbal, visual, logical, musical, mathematical, creative, physical, emotional, spatial) do not appear to be cross-linked at this time.