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

232 Educability and Group Differences
environmental causes. As already noted, environmentalists often
differ in the particular kinds of traits and groups to which they extend
their insistence upon a wholly environmental explanation of
human differences. This tendency results in the uncritical acceptance
of almost any environmental factor that anyone suggests
as an explanation, regardless of its often purely ad hoc status, its
inconsistency with other data, and often the failure even to show
any correlation, much less causation, between the suggested environmental
causes and the behavioral traits in question. Since an
environmental explanation is decreed as necessary and sufficient,
almost any environmental factor will do, without the need to
demonstrate its causal connection, or even correlation, with
intelligence or scholastic achievement. Some environmental factors
are formulated clearly enough to be put to the test of evidence; as
each of the hypothesized factors is rejected on the basis of evidence,
other increasingly subtle environmental deficits are postulated to
explain the differences. Baratz and Baratz (1970, p. 35) have noted
this tendency in various attempts to account for the failure of
intervention programs such as Head Start to appreciably raise
IQ and scholastic performance:
Postulation of one deficit which is unsuccessfully dealt with by
intervention programs then leads to the discovery of more basic
and fundamental deficits. Remediation or enrichment gradually
broadens its scope of concern from the fostering of language
competence to a broad-based restructuring of the entire cultural
system. The end result of this line of argument occurs when
investigators such as Deutsch and Deutsch (1968) postulate
that ‘some environments are better than others’.
Inconsistencies abound in environmentalist arguments. Unrelated
children adopted at birth and reared together are much less alike
in IQ than true siblings, it is said, because of subtle factors within
the family environment which makes them dissimilar in intelligence.
In the next breath it is argued that identical twins reared
apart in different families are highly similar in IQ because of subtle
influences common to both families (though they may be at opposite
ends of the SES spectrum and have no knowledge of one another)
which make for a high correlation between the twins’ IQs. How
often do we see environmentalists propose any experiment,
statistical study, type of evidence, or any combination thereof,