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

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variables
Equating for socioeconomic
In comparative studies of the mental abilities of racial groups,
environmentalists are most insistent that the racial samples being
compared on intelligence be matched, or otherwise equated, on
indices of socioeconomic status (SES), which usually includes
father’s occupation, education of parents, income, quality of
housing, and place of residence. When groups are thus ‘equated’
and a substantial mean IQ difference still shows up, it is claimed
that not enough environmental factors were controlled. As one
sociologist put it: ‘. . . the kinds of socioeconomic measures that
have been used so far in attempting to control on environmental
effects appear to omit a wealth of cultural and psychological factors’.
This is a testable hypothesis; it should be determined how much
the cultural and psychological factors (assuming they can be
specified and measured) add to the multiple R 2 with IQ over and
above the R 2 yielded by good indices of SES.
But the whole notion of equating for SES, in the first place,
involves what has been called the ‘sociologist’s fallacy’. This fallacy
is seen in full bloom in one sociologist’s criticism of studies of
Negro-white IQ differences which equated the groups for SES
or other environmental factors: ‘Actually in most of the studies he
[Jensen, 1969a] reports on, the most important environmental
variable, the IQ of the parent, has not been equated at all’
(Stinchcombe, 1969, p. 516). Apart from the strictly environmental
effect of parental IQ,1 it is obvious that, since IQ variance contains
a large genetic component, equating groups for parental IQ means
equating them for genetic factors more than for environmental