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

Culture-biased Tests 315
that ‘Correlations with Piaget item composites of six and eight
items respectively are 0-60 for the Raven v. 0-21 for the Peabody’.
These are the kinds of correlations one should expect if Piaget’s
tests are culture-reduced, since among psychometric tests the
Peabody and the Raven are probably further apart than any other
tests on the continuum going from ‘culture-loaded’ to ‘culturefree’.
Do the Piagetian tests have high heritability It would be most
surprising if they did not, in view of what has just been said,
although there have not yet been any heritability studies of these
tests. One impressive study, however, strongly supports the idea
that Piagetian tests are highly sensitive indicators of genetic
factors in mental development. DeLemos (1969) administered a
battery of Piagetian tests to Australian Aborigines, ages 8 to 15
years. The Aboriginal children were remarkedly retarded as
compared with European and American norms. The majority of
adolescents were still not up to the level attained by the average
European 7-year-old. Even the majority of Aboriginal adults do
not reach the level of concrete operations represented by the
conservation of quantity and volume, although there are a few
exceptions. In the course of this study, DeLemos compared the
Piagetian test performances of full-blooded Aborigines with those
who were part Aboriginal and part Caucasian. The children’s
ancestry was known from records kept by the mission in charge of
the territory inhabited by these Aborigines. It is unclear whether
any intellectually selective factor was involved in the Aborigine-
Caucasian matings. The Caucasian ancestors were ‘casual’, probably
being immigrant laborers and sailors, and never lived among
the tribe.
Among the children classified as part-Aborigines the degree of
European ancestry was small, the majority being classified as £th
Aboriginal [the equivalent of having one Caucasian greatgrandparent].
The European ancestry was therefore several
generations removed from the present group. There were no
apparent differences in the present environment of the part-
Aboriginal and full-Aboriginal children. . . . Part-Aborigines
and full-Aborigines formed a single integrated community, and
the children were brought up under the same mission conditions
and attended the same school. (DeLemos, 1969, p. 257)