Intelligence: heredity versus environment
[SOURCE: Fulcher, J. & Scott, J. (2011). Pp 731-2. Sociology (4th ed.). Oxford: Oxford University Press.]
Various attempts have been made to explain where intelligence comes from. In the
nineteenth and twentieth centuries the essential argument of heredity versus
environment emerged. These terms are often known as ‘nature’ and ‘nurture’
respectively. Essentially, the arguments are concerned with the extent to which
intelligence is inherited through the genes a person is born with (heredity, or nature),
or formed through a person’s life and their surroundings (environment, or nurture).
These theories led to the concept of how to measure intelligence. Early attempts at
measuring intelligence (eg. Galton, 1869) associated it with social inequalities.
According to this point of view, the role of environmental factors had to be recognized
alongside the part played by heredity. This work led to the construction of IQ
(intelligence quotient) tests to measure intelligence. The measurement of IQ originated
in the work of the statistician Spearman (1904), who introduced the concept of ‘g’
(general intelligence) to describe the general cognitive ability that he thought lay
behind specific abilities and forms of intelligence (linguistic, mathematical, spatial,
musical, etc.). The development of these tests seemed to promise the possibility that the
relationship between material inequalities and social inequalities could be studied with
mathematical precision.
Arguments that link inherited intelligence to a person’s social situation rest on several
assumptions, including:
General intelligence (g) is a cognitive ability that underlies all other specific
forms of intelligence and can be accurately measured by IQ tests.
Measures of social advantage and disadvantage correlate highly with measures
of general intelligence. Because the distribution of advantages and disadvantages
reflects the distribution of intelligence, it can be seen as determined by
differences in general intelligence.
Intelligence is genetically determined. It is, therefore, fixed from birth: education
and other environmental factors have little or no effect on the level of
intelligence.
Each of these assumptions can be questioned. The concept of general intelligence has
been heavily criticized, and there is no agreement that there is any such common factor
behind particular abilities. Mathematical and verbal intelligence, for example, are not
perfectly associated with one another. It may be more useful to regard intelligence as a
set of intellectual capacities rather than a single one. Even if it is allowed that general
intelligence exists, however, there is the problem of how it is to be measured.
Many have questioned the value of the IQ score as a measure of intelligence. Tests have
been shown to be culturally biased towards Western (American and European) culture
and, within this, towards white, middle-class men. The cultural differences that shape
the ability to perform in the tests do not necessarily reflect any differences in
intelligence. More fundamentally, perhaps, there are doubts about whether
performance in pencil-and-paper tests can be a proper measure of a person’s ability to
perform in ‘real’ situations. Indeed, there are wider doubts about whether performance
in A-level, degree, or other examinations is an adequate measure of a person’s
understanding of a subject or ability to apply it in real-life situations.
Intelligence is a complex process that brings together numerous aspects of brain
function, and doubts have been raised about its genetic bias. It is inherited not as a fixed
quantity but as a capacity to learn the kinds of skills and understandings that make up a
particular ability. The realization of this capacity depends on the stimulation that is
received in the first few years of life and, to a much lesser extent, in later life. It has been
found that per-school, primary socialization is critical in raising or lowering measure
intelligence. Formal education can have a continuing, if smaller, effect, and educational
action programmes can significantly raise the IQ of children who enter them with
relatively low IQ. Cross-cultural studies have shown that the relatively high IQ of East
Asians, as compared with North Americans, is due to the length and type of schooling,
the extent of parental support, and the cultural support for disciplined work.
