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

302 Educability and Group Differences
culture-reduced tests show negligible loadings on verbal and
numerical factors. (3) Culture-reduced tests show significantly
less relationship with socioeconomic status than do conventional
tests. (4) A conventional test (California Test of Mental Maturity)
showed a significant increase in relationship with socioeconomic
status over four years, whereas the Progressive
Matrices showed no change. (5) Verbal items from the CTMM
showed greater variation in Item discrimination between social
classes than did items from the Progressive Matrices, (p. 118)
The Progressive Matrices Test has been used in numerous truly
cross-cultural studies. These studies show mean differences between
various ethnic and cultural groups the directions of which are
not at all in accord with the popular notion that groups are
handicapped on IQ tests directly in relation to their degree of
environmental and cultural dissimilarity from that of the white
middle- and upper-middle class population of the United States
or Western Europe. It would be hard to find an environmentally
and culturally more dissimilar group than the Eskimos living in
the icy wastes far above the Arctic circle. Yet representative
samples of these Eskimos score at or above white Canadian norms
on the Progressive Matrices (MacArthur, 1968). Berry (1966)
found Eskimo samples scoring near his Scottish samples (one of
the highest normative groups) on the Progressive Matrices and
the Embedded Figures Tests. Vernon too, has found that
on the Matrices and similar tests, such as the Kohs Block Designs
and Abstractions, Eskimos and Canadian Indians score much
higher than Jamaican Negroes. Vernon seeks an environmental
explanation of the marked disparity:
Now economic conditions are extremely poor in all three groups
(Eskimos, Indians, Jamaicans), and there is similar family
instability and insecurity. Thus it seems reasonable to attribute
the better performance of Eskimo and Indian groups to the
greater emphasis on resourcefulness in the upbringing of boys,
perhaps combined with their strong masculine identification.
True, the traditional hunting-trapping life is rapidly disappearing
and the majority of parents are wage earning or on relief,
but the children are still brought up permissively and encouraged
to explore and hunt. Moreover, a subgroup of the Eskimos who
came from the most isolated Arctic communities scored better