Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, October 23, 1994 TAG: 9410240031
SECTION: NATIONAL/INTERNATIONAL PAGE: NATL/INTL EDITION: METRO
SOURCE: Knight-Ridder/Tribune
DATELINE: WASHINGTON LENGTH: Long
Race, America's rawest nerve, is throbbing again.
Scholars and scientists, government officials and opinion leaders are in an uproar this fall over newly published works linking heredity, intelligence and human behavior.
At the same time, white politicians of both parties are demanding a cutoff of welfare to unwed mothers and harsh punishment for teen-age criminals - many of them sons and daughters of generations of troubled parents. The leader of the Illinois Senate refused to apologize for asserting that minority state employees don't work as hard as whites.
President Clinton is said to be ``outraged'' by a book, ``The Bell Curve,'' which asserts that blacks, as a group, are less intelligent than whites. The Rev. Jesse Jackson called the 845-page book - which recommends that government do less to help disadvantaged people - a ``recapitulation of ancient garbage.''
Written by two conservative scholars, Charles Murray and the late Richard Herrnstein, ``The Bell Curve'' follows a mounting wave of scientific and social research exploring three separate but related questions:
Do the genes you inherit from your parents affect your intelligence and your behavior?
Are there measurable differences in mental ability between blacks and whites?
How should society deal with people who have different abilities and personal qualities?
On the first point, the scientific evidence is strong that genes do matter.
A broad consensus has developed in recent years among biologists, geneticists and psychologists - if not the general public - that heredity plays a significant role in mental and emotional as well as physical development.
But authorities say genes are not the whole story; they contribute to but do not control human destiny. Your environment - your home, neighborhood, school, job, the sum of your life experiences - are equally if not more important.
``The operations of the brain result from a balance between inputs from heredity and environment, from nature and from nurture,'' said Torsten Wiesel, president of Rockefeller University in New York.
This new scientific consensus is a change from the time after World War II, when the terrible misuse of genetics by Nazi Germany led to a near total rejection of the role of heredity in human development.
``Just 15 years ago, the idea of genetic influence on complex human behavior was anathema to many behavioral scientists,'' according to Robert Plomin, director of the Center for Developmental and Health Genetics at Pennsylvania State University. ``Now, however, the role of inheritance in behavior has become widely accepted, even for sensitive domains such as IQ.''
Plomin and other researchers base their conclusions, in part, on studies of the intelligence and personality traits of twins, siblings and adopted children in thousands of families.
More than 30 studies comparing more than 10,000 pairs of twins found that identical twins, who carry the same genes, consistently shared more characteristics - such as verbal ability and spatial reasoning - than fraternal twins. Identical twins were about twice as likely to perform comparably in school and choose similar careers as were fraternal twins, who have only half their genes in common. Other brothers and sisters showed greater differences than twins.
Similar studies by Plomin's group revealed that adopted kids bore little resemblance to their adoptive parents or to other children raised in the same home.
Thus the more genes any two persons shared, the more alike they were, regardless of external influences.
The federal government's Human Genome Project, which seeks to identify all 100,000 human genes, is beginning to find connections between certain genes and various mental and emotional conditions that affect success in life.
This month, scientists reported they apparently have located a gene on chromosome 6 that is associated with dyslexia, a reading disability afflicting millions of people.
Three years ago, a common form of mental retardation was linked to a flawed gene on the X chromosome. Also, Alzheimer's disease, which destroys the minds of many elderly persons, has been shown to have genetic roots.
No single ``IQ gene'' has been found, however, and scientists doubt such a thing exists. Tentative reports of the discovery of a ``violence gene,'' a ``gay gene'' and an ``alcoholism gene'' have not been confirmed.
Instead, the prevailing wisdom is that intelligence and personality are the products of a complex and subtle interplay between hundreds, perhaps thousands of genes, along with a vast tangle of environmental influences.
``The normal range of behavioral variation is orchestrated by a system of many genes, each with small effects,'' Plomin said. ``We need to find many tiny needles in the haystack.''
Murray and Herrnstein estimated that heredity is responsible for between 40 percent and 80 percent of the variability in humans, a range so wide as to be almost meaningless.
In their book, they settle on 60 percent as an average, which would make genes more important than external influences. Others rank heredity well below environment - some say as low as 10 percent to 20 percent.
``Usually, genetic factors do not account for more than about half of the variance for behavioral disorders and dimensions,'' Plomin said. ``The current enthusiasm for genetics should not obscure the important contribution of non-heritable factors.''
The well-established connection between genes and intelligence becomes explosive when it is linked to race, as Murray and Herrnstein do.
The evidence that race determines intelligence and behavior is murky and open to challenge.
It is generally accepted that, on average, whites score better on standard IQ tests than blacks, but the meaning of this phenomenon is unclear. It is often attributed to cultural bias and the social disadvantages that many blacks suffer.
A textbook on human genetics published this year by Elaine and Arthur Mange of the University of Massachusetts summarizes current knowledge: ``The major undisputed fact about the IQ scores among black and white children is that the average racial difference is about 15 points.''
The Manges hasten to point out that there is considerable overlap in black and white scores: Many, many blacks do better than many, many whites.
``The IQ score of a particular individual is no guide to his or her race and vice versa,'' their textbook states.
Furthermore, some experts say IQ tests are not a good measure of real intelligence and do not reliably predict success or failure. Many factors are important in life besides braininess: energy, health, ambition, social skills, good looks, even height and weight.
The reasons for the racial disparity in IQ tests are hotly disputed.
As does Jesse Jackson, some blame blacks' lower scores on broken homes, bad schools, poverty and racism. Murray and Herrnstein, however, claim some differences remain even when environmental factors are accounted for, and they attribute this ``residue'' to heredity.
Critics also say the test questions are unfair to blacks living in poverty who lack the cultural advantages of middle-class whites.
Murray and Herrnstein deny that intelligence tests are biased. They contend that some tests, such as repeating a sequence of numbers backward or reacting quickly to a flashing light, measure mental agility and not culture.
``The black/white difference is wider on items that appear to be culturally neutral than on items that appear to be culturally loaded,'' they wrote.
There is even less agreement on the third issue in the controversy: what society should do about racial differences.
Murray and Herrnstein are longtime skeptics of government programs to improve the conditions of what they term the ``underclass.'' In their book, they assert that heredity determines so much of a person's capacity to succeed that there is little point trying to achieve an impossible equality.
``No one knows how to raise low IQs substantially on a national level,'' they wrote. ``To think that the available repertoire of social interventions can do the job if only the nation spends more money on them is illusory.''
Thus they dismiss Head Start, the popular program to help preschool children, as ineffective. After a few years in school, they say, its benefits fade away.
Admitting that they are being ``elitist,'' the two scholars suggested that ``some federal funds now so exclusively focused on the disadvantaged should be reallocated to programs for the gifted,'' on the theory that intellectual gains at the top of the social ladder will trickle down and benefit everyone.
In addition, Murray and Herrnstein would end affirmative action programs intended to help minorities get jobs. They also would overturn a 1971 Supreme Court ruling forbidding employers to use IQ tests.
Their proposals have provoked an indignant response.
``Inegalitarian, ungenerous and as reactionary as anything I have read in years,'' wrote Alan Wolfe, author of a book on human differences, in a commentary in The New Republic.
Some readers of ``The Bell Curve'' contend that the possible link between race and intelligence is so inflammatory that it should not be discussed publicly at all. Glenn Loury, a black professor at Boston University, said talk of racial differences could be ``terribly destructive'' if it is not coupled with useful action.
Others say it is better to bring unpleasant topics into the open, to be debated and perhaps refuted. Andrew Sullivan, editor of The New Republic, overruled protests from his staff and ran a long extract from the book as its cover story last week.
``To say that a debate cannot be had is to enforce a taboo utterly at odds with free inquiry,'' Sullivan wrote.
by CNB