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

344 Educability and Group Differences
Further, in the case of the black sample, the frequency of
maximal brain damage exceeded the frequency of minimal brain
damage - constituting, therefore, a direct reversal of the
minimal-maximal severity pattern observed in the case of the
whites. It is apparent, then, that the black population of children
is characterized not only by higher overall rates of brain damage
relative to the white population, it is also characterized by more
severe cases of brain damage. (Amante et al., 1970, p. 126)
Later in their discussion of the results, the authors state, ‘We wish
to avoid the implications of racism.’ And buried among the several
following paragraphs discussing the sociology of racism is put
forth what amounts to a major testable hypothesis:
Large groups of white or black Ss of varying socioeconomic
status are typically uncritically selected and tested with conventional
psychometric instruments. Naturally, major differences
between the classes and the races are indicated. In all
probability the observed differences are largely a function of the
fact that the groups so selected contain an unspecified number
of neurologically handicapped Ss, and these Ss pull the group
averages down. If the entire group was neurologically screened
to begin with, and the neurologically normal or deviant Ss
appropriately compared with other Ss of similar neurological
status, and the conventional tests then administered, the supposedly
obvious or inevitable IQ differentials between the
groups might collapse to zero and/or statistical insignificance,
(p. 129)6
These investigators seem to be ambivalent, however, since they
finally state:
Our final conclusion is that there are interclass and interracial
differences in terms of measurable intelligence; both environmental
and genetic factors appear to contribute to these IQ
differentials. At the present time we are assuming that the major
factors contributing to group differences are environmental in
nature, (p. 129)7
At present there are two lines of evidence that seem incompatible
with the hypothesis of such a high incidence of brain damage as