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

284 Educability and Group Differences
Students of language development recognize that it is largely
under the control of innate factors. Lenneberg (1969, p. 638) has
reported studies of language acquisition in monozygotic and
dizygotic twins, permitting analysis of genetic influences. Individual
differences in the age of language acquisition, the rate of development,
and the specific types of problems encountered all show a
high degree of genetic determination. (Also see Lenneberg, 1967.)
Vocal language, as a species-specific characteristic, does not
need to be built up or shaped laboriously through the conditioning
and chaining of myriads of behavioral units. Language is learned,
to be sure, but learning a species-specific form of behavior is quite
different, in terms of individual differences, from the learning of
many other kinds of behavioral repertoires. In species-specific
behaviors learning capacity for a class of behaviors has been more
or less maximized and individual differences minimized; there is
relatively little individual genetic variation, but so much genetic
determination for the ease of acquisition of certain behaviors that
capricious environmental contingencies, within very wide limits,
have little effect on the acquisition of the behavior. (We often therefore
tend to call it ‘development’ rather than ‘acquisition’.) Houston
(1970), a psycholinguist, points out that
. . . all children learn language merely by being placed in the
environment of the language and . . . they do not need any
special training or conditioning whatever to achieve this [four
references]. Further, all children appear to learn language in
about the same length of time, namely, from four to six years.
. . . Given the open-ended variation in learning environments
previously noted and given the lack of directed reinforcement for
language or other behavior in children characteristic of many
societies, the argument for a biological basis for language
acquisition is convincing.. . . It is now believed by linguists that
man has an innate biological capacity for language acquisition,
a capacity which has been described as a species-specific and
species-uniform language-acquisition device which functions
uniquely in the language-acquisition process and the operation
of which is constant for all children. Various biological and
neurophysiological correlates of the language-learning process
have been discovered, so that this position is strengthened,
(pp. 949-50)