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

74 Educability and Group Differences
presumably the same for the knowledge and skills sampled by
intelligence tests as for those sampled by scholastic achievement
tests. In a sense, when we use intelligence tests to predict scholastic
achievement, what we are doing is using achievement in one
domain (non-scholastic) to predict achievement in another
(scholastic).
The most obvious difference between tests of intelligence and of
achievement is the breadth of the domains sampled by the tests.
Achievement tests sample very narrowly from the most specifically
taught skills in the traditional curriculum, emphasizing the 3 Rs.
The test items are samples of the particular skills and items of
information that children are specifically taught in school. Since
this domain is quite explicitly defined and the criteria of its
acquisition are fairly clear to teachers and parents, children can
be taught and made to practise these skills so as to shape their
performance up to the desired standard. Because of the circumscribed
nature of many of the basic scholastic skills, the pupil’s
specific weaknesses can be identified and remedied.
The kinds of skills and learning sampled by an intelligence test,
on the other hand, represent achievements of a much broader
nature. Much of what is tapped by IQ tests is acquired by incidental
learning, that is to say, it has never been explicitly taught. Most
of the words in a person’s vocabulary were never explicitly taught
or acquired by studying a dictionary. Intelligence test items
typically are sampled from such a wide range of potential experiences
that the idea of teaching intelligence, as compared with
teaching, say, reading and arithmetic, is practically nonsensical.
Even direct coaching and practice on a particular intelligence test
raises an individual’s scores on a parallel form of the test on the
average by only five to ten points; and some tests, especially those
referred to as ‘culture fair’, seem to be hardly amenable to the
effects of coaching and practice. The average five-year-old child,
for example, can copy a circle or a square without any trouble,
but try to teach him to copy a diamond and see how far he gets!
It is practically impossible. But wait until he is seven years old
and he will have no trouble copying the diamond, without any
need for instruction. Even vocabulary is very unsusceptible to
enlargement by direct practice aimed specifically at increasing
vocabulary.
This is mainly the reason that vocabulary tests are such good