I
magine several hundred families which face few of the usual problems
that plague modern society. Unemployment is zero. Illegitimacy is zero.
Divorce is rare and occurs only after the children's most formative
years. Poverty is absent indeed, none of the families is anywhere near
the poverty level. Many are affluent and all have enough income to live
in decent neighbourhoods with good schools and a low crime rate.
If you have the good fortune to come from such a background, you will
expect a bright future for your children. You will certainly have
provided them with all the advantages society has to offer. But suppose
we follow the children of these families into adulthood. How will they
actually fare?
A few years ago the late Richard Herrnstein and I published a
controversial book about IQ, The Bell Curve, in which we said that much
would depend on IQ. On average, the bright children from such families
will do well in life and the dull children will do poorly. Unemployment,
poverty and illegitimacy will be almost as great among the children from
even these fortunate families as they are in society at large not quite
as great, because a positive family background does have some good
effect, but almost because IQ is such an important factor.
"Nonsense!" said the critics. "Have the good luck to be born to the
privileged and the doors of life will open to you including doors that
will let you get a good score in an IQ test. Have the bad luck to be
born to a single mother struggling on the dole and you will be held down
in many ways including your IQ test score." The Bell Curve's purported
relationships between IQ and success are spurious, they insisted:
nurture trumps nature; environment matters more than upbringing.
An arcane debate about statistical methods ensued. Then several American
academics began using a powerful, simple way of testing who was right:
instead of comparing individual children from different households, they
compared sibling pairs with different IQs. How would brothers and
sisters who were nurtured by the same parents, grew up in the same
household and lived in the same neighbourhood, but had markedly
different IQs, get on in life?
The research bears out what parents of children with unequal abilities
already know that try as they might to make Johnny as bright as Sarah,
it is difficult, and even impossible, to close the gap between them.
A very large database in the United States contains information about
several thousand sibling pairs who have been followed since 1979. To
make the analysis as unambiguous as possible, I have limited my sample
to brothers and sisters whose parents are in the top 75 per cent of
American earners, with a family income in 1978 averaging 40,000 (in
today's money).
Families living in poverty, or even close to it, have been excluded. The
parents in my sample also stayed together for at least the first seven
years of the younger sibling's life.
Each pair consists of one sibling with an IQ in the normal range of
90-110 a range that includes 50% of the population. I will call this
group the normals. The second sibling in each pair had an IQ either
higher than 110, putting him in the top quartile of intelligence (the
bright) or lower than 90, putting him in the bottom quartile (the dull).
These constraints produced a sample of 710 pairs.
How much difference did IQ make? Earned income is a good place to begin.
In 1993, when we took our most recent look at them, members of the
sample were aged 28-36. That year, the bright siblings earned almost
double the average of the dull: 22,400 compared to 11,800. The normals
were in the middle, averaging 16,800.
These differences are sizeable in themselves. They translate into even
more drastic differences at the extremes. Suppose we take a salary of
50,000 or more as a sign that someone is an economic success. A bright
sibling was six-and-a-half times more likely to have reached that level
than one of the dull. Or we may turn to the other extreme, poverty: the
dull sibling was five times more likely to fall below the American
poverty line than one of the bright.
Equality of opportunity did not result in anything like equality of
outcome. Another poverty statistic should also give egalitarians food
for thought: despite being blessed by an abundance of opportunity, 16.3%
of the dull siblings were below the poverty line in 1993. This was
slightly higher than America's national poverty rate of 15.1%.
Opportunity, clearly, isn't everything. In modern America and also, I
suspect, in modern Britain it is better to be born smart and poor than
rich and stupid.
Another way of making this point is to look at education. It is often
taken for granted that parents with money can make sure their children
get a college education. The young people in our selected sample came
from families that were overwhelmingly likely to support college
enthusiastically and have the financial means to help. Yet while 56% of
the bright obtained university degrees, this was achieved by only 21% of
the normals and a minuscule 2% of the dulls. Parents will have been
uniformly supportive, but children are not uniformly able.
The higher prevalence of college degrees partly explains why the bright
siblings made so much more money but education is only part of the
story. Even when the analysis is restricted to siblings who left school
without going to college, the brights ended up in the more lucrative
occupations that do not require a degree, becoming technicians, skilled
craftsmen, or starting their own small businesses. The dull siblings
were concentrated in menial jobs.
The differences among the siblings go far beyond income. Marriage and
children offer the most vivid example.
Similar proportions of siblings married, whether normal, bright or dull
but the divorce rate was markedly higher among the dull than among the
normal or bright, even after taking length of marriage into account.
Demographers will find it gloomily interesting that the average age at
which women had their first birth was almost four years younger for the
dull siblings than for the bright ones, while the number of children
born to dull women averaged 1.9, half a child more than for either the
normal or the bright.
Most striking of all were the different illegitimacy rates. Of all the
first-born children of the normals, 21% were born out of wedlock about a
third lower than the figure for the United States as a whole, presumably
reflecting the advantaged backgrounds from which the sibling sample was
drawn. Their bright siblings were much lower still, with less than 10%
of their babies born illegitimate. Meanwhile, 45% of the first-born of
the dull siblings were born outside of marriage.
The inequalities among siblings that I have described are from 1993 and
are going to become much wider in the years ahead. The income trajectory
for low-skill occupations usually peaks in a worker's twenties or
thirties. The income trajectory for managers and professionals usually
peaks in their fifties. The snapshot I have given you was taken for an
age group of 28-36 when many of the brights are still near the bottom of
a steep rise into wealth and almost all the dulls' incomes are stagnant
or even falling.
Add to this the income of spouses. With divorce higher among the dulls,
the availability of a second income becomes lower. Among those who
remain married, the brights profit more because of what sociologists
call "assortative mating". The bright tend to marry the bright, who also
tend to be in occupations that will give them large and increasing
incomes. The dull tend to marry the dull, who also tend to be in
low-paying jobs or are even unemployed.
The inequalities I have presented are the kind you are used to seeing in
articles that compare inner-city children with suburban ones, black with
white, children of single parents with those from intact families. Yet
they refer to the children of a population more advantaged in jobs,
income and marital stability than even the most starry-eyed social
reformer can hope to achieve.
You may be wondering whether the race, age or education of siblings
affects my figures. More extended analyses exist, but the short answer
is that the phenomena I have described survive such questions. Siblings
who differ in IQ also differ widely in important social outcomes, no
matter how anyone tries to explain away the results. Ambitious parents
may be dismayed by this conclusion, but it is none the less true for all
that.
A final thought: I have outlined the inequalities that result from
siblings with different IQs. Add in a few other personal qualities
industry, persistence, charm and the differences among people will
inevitably produce a society of high inequalities, no matter how level
the playing field has been made. Indeed, the more level the playing
field, and the less that accidents of birth enter into it, the more
influence personal qualities will have.
I make this point as an antidote to glib thinking on both sides of the
Atlantic and from both sides of the political spectrum. Inequality is
too often seen as something that results from defects in society that
can be fixed by a more robust economy, more active social programmes, or
better schools. It is just not so.
The effects of inequality cannot be significantly reduced, let alone
quelled, unless the government embarks on a compulsory redistribution of
wealth that raises taxes astronomically and strictly controls personal
enterprise.
Some will call this social justice. Others will call it tyranny. I side
with the latter, but whichever position one takes, it is time to stop
pretending that, without such massive compulsion, human beings in a fair
and prosperous society will ever be much more equal than they are now.