Study gives more proof that intelligence is largely inherited

Binet is a hero to many psychologists. He was a keen observer, a careful scholar, an inventive technologist. Perhaps even more important for his followers, he devised the instrument that is often considered psychology's greatest success story.
Millions of people who have never heard Binet's name have had aspects of their fate influenced by instrumentation that the French psychologist inspired. And thousands of psychometricians -- specialists in the measurement of psychological variables -- earn their living courtesy of Binet's invention. Although it has prevailed over the long run, the psychologists' version of intelligence is now facing its biggest threat.
Many scholars and observers -- and even some iconoclastic psychologists -- feel that intelligence is too important to be left to the psychometricians. Experts are extending the breadth of the concept -- proposing many intelligences, including emotional intelligence and moral intelligence. They are experimenting with new methods of ascertaining intelligence, including some that avoid tests altogether in favor of direct measures of brain activity.

The public is more interested in the second question: Is intelligence (or are intelligences) largely inherited? This is by and large a Western question. In the Confucian societies of East Asia individual differences in endowment are assumed to be modest, and differences in achievement are thought to be due largely to effort. In the West, however, many students of the subject sympathize with the view -- defended within psychology by Lewis Terman, among others -- that intelligence is inborn and one can do little to alter one's intellectual birthright.
Studies of identical twins reared apart provide surprisingly strong support for the "heritability" of psychometric intelligence. That is, if one wants to predict someone's score on an intelligence test, the scores of the biological parents (even if the child has not had appreciable contact with them) are more likely to prove relevant than the scores of the adoptive parents. By the same token, the IQs of identical twins are more similar than the IQs of fraternal twins. And, contrary to common sense (and political correctness), the IQs of biologically related people grow closer in the later years of life. Still, because of the intricacies of behavioral genetics and the difficulties of conducting valid experiments with human child-rearing, a few defend the proposition that intelligence is largely environmental rather than heritable, and some believe that we cannot answer the question at all.
Most scholars agree that even if psychometric intelligence is largely inherited, it is not possible to pinpoint the sources of differences in average IQ between groups, such as the fifteen-point difference typically observed between African-American and white populations. That is because in our society the contemporary -- let alone the historical -- experiences of these two groups cannot be equated. One could ferret out the differences (if any) between black and white populations only in a society that was truly color-blind.

Last Updated: Tuesday, 3 October 2006, 23:39 GMT 00:39 UK

Breast milk 'does not boost IQ'

Breastfed babies tend to be brighter
Breastfed babies are smarter because their mothers are clever in the first place, not because of any advantage of breastfeeding itself, a study suggests.
Researchers found breastfeeding mothers tended to be more intelligent, more highly educated, and likely to provide a more stimulating home environment.

However, they stressed that there were still many advantages to breastfeeding.

The British Medical Journal study was carried out by the Medical Research Council and University of Edinburgh.

It is important that women make a decision that is right for them

Rosie Dodds
National Childbirth Trust

Lead researcher Geoff Der said: "This question has been debated ever since a link between the two [high IQ and breastfeeding] was first discovered in 1929.

"Breastfed children do tend to score higher on intelligence tests, but they also tend to come from more advantaged backgrounds."

The researchers analysed data from more than 5,000 children and 3,000 mothers in the US.

They found that mothers who breastfed tended to be more intelligent, and when this fact was taken into account, most of the relationship between breastfeeding and the child's intelligence disappeared.

The rest was accounted for by other aspects of the family background.

Sibling comparison

The researchers also looked at families where one child was breastfed and another was not.

This confirmed the earlier results - the breastfed child was no more intelligent than his or her sibling.

Putting the results together with other studies that measured the mother's IQ confirmed this pattern.

Mr Der said: "This research shows that intelligence is determined by factors other than breastfeeding.

"But breastfeeding has many benefits for both mother and child. It's definitely the smart thing to do."

Breastfeeding has been linked to a range of health benefits.

Just one day of breastfeeding is thought to be enough to stabilise a baby's blood sugar levels, and provide natural antibodies against disease.

Breastfed babies have been shown to be less prone to diarrhoea, vomiting, and respiratory infections. Breastfeeding may also have a long impact on reducing blood pressure and obesity.

The World Health Organization recommends that babies should be breastfed for at least the first two years.

The UK has one of the lowest breastfeeding rates in Europe - almost a third of women in England and Wales never try to breastfeed, compared with just 2% in Sweden.

Low rates

Rosie Dodds, of the National Childbirth Trust, said the study was not conclusive.

She said a study in the Philippines - where, unlike the West, poorer women are more likely to breastfeed - showed that breastfed children were likely to be more intelligent.

However, she added: "Women do not breastfeed because of any benefit to their baby, they do it because it feels like the natural thing to do.

"It is important that women make a decision that is right for them, and their family, and they should not be pressurised either way, but we would like to see more support for women who do decide they want to breastfeed."

The Department of Health said breastfeeding was the best form of nutrition for infants.

"We know that the composition of breast milk meets the individual needs of each baby and that, as a result, breastfeeding can make a major contribution to public health."

..such as the fifteen-point difference typically observed between African-American and white populations

.........Put me on a desert island where I have to survive by fishing, putting up traps and climb trees to get some fruit. I would have in this area an IQ of 10.