Educability-and-Group-Differences-1973-by-Arthur-Robert-Jensen

Technical Misconceptions and Obfuscations 67
persons in upper and middle management positions, while they
are not thought of as being the intellectual elite, actually turn out,
on the average, to be at the ninety-sixth percentile of the white
population in intelligence, equivalent to an IQ of about 125
(Ghiselli, 1963). Many more whites than Negroes per capita fall
above this point.
But perhaps the more serious consequences of the la mean
difference are at the lower extreme of the distribution. Persons
who have been exposed to schooling for several years but who still
have IQs below 70, especially on non-verbal and non-scholastic
tests, are severely handicapped in the world of work, and can
seldom succeed in any kind of skilled or semi-skilled work available
in an industrial society. Most of them have difficulty finding
employment in an urban economy and they are frequently dependent
either upon relatives or public welfare for their support.
Persons in our society today with IQs below 70 are generally
regarded as mentally retarded and in school would be recognized
as such even if there were no IQ tests. This degree of handicap
cannot be passed off lightly as a ‘cultural difference’, because the
behavioral correlates of an IQ below 70 are probably a handicap
in any modern culture. Again, from the properties of the normal
curve, any population subgroup whose mean is ler below IQ 100
can be expected to have approximately seven times as many
persons with IQs under 70 as are found in a population whose
mean IQ is 100. From a social standpoint, this is probably the
gravest consequence of the average Negro-white IQ difference.
If as many as one-sixth to one-fourth of the members of a community
have IQs below 70, it is difficult to imagine that the
quality of the environment would not be adversely affected. If
the quality of the environment depends to some extent upon the
intelligence of the persons who create the environment, we cannot
argue, as some social scientists would do, that subpopulation
intelligence differences can only be studied after complete environmental
equality has been achieved, in which case presumably all
differences would be eliminated and there would no longer be a
problem calling for solution. Realistically, improving the environment
in psychologically significant ways may depend even more
upon improving the intelligence of its inhabitants than raising
their intelligence depends upon improving the quality of their
environment.