A CREATIVE COGNITION 231functioning. In contrast, a less- strict nativist would argue that diff erences
in cognitive hardware will result from random gene mutations. And these
will put individuals on a ge ne tic ladder of ability. Th is is the model of
the behavioral ge ne ticist who adopts meta phors like speed and power to
describe the hardware diff erences.
However, nearly every one agrees that the gene- directed variation in
that model will be attenuated by the environment and experience. Usu-
ally, some level of associationism is incorporated in the form of learning
ability. So we get a mixture of sources of variation, as in the con temporary
nature- nurture debate.
Under constructivism, individual diff erences emerge from experiences
in development in a way that transcends simple associations and built-in
nativist functions. Th is does not preclude the possibility of individual
diff erences forming from ge ne tic and environmental diff erences. It is
just that their respective eff ects will be more concealed in the workings
of the system.
In this chapter, I have put forth another point of view: that of active
organisms incorporating environmental structures and changing their
own structures and functions to accommodate them. Th is view refl ects
the extensive evidence that systems have evolved with many buff ering
mechanisms and ways of varying in adaptive, creative ways. Nearly all
individuals will have good enough systems for assimilating structures of
experience and actively generating individual diff erences accordingly.
Aft er that, to quote Eric Turkheimer again, “behaviour emerges out of a
hyper- complex developmental network into which individual genes and
individual environmental events are inputs. Th e systematic causal eff ects
of any of those inputs are lost in the developmental complexity of the
network.”^24
Of course, rare deleterious gene mutations— the absence of a crucial
ingredient— might result in disorders at any of these levels. Absence of
specifi c environmental components, or toxic insults, may do likewise (see
chapter 10). Such mutations and insults result in distinct categorical vari-
ants, not extremes of a normal distribution, or a ladder of ability.
In general, however, causal explanations of individual diff erences in
complex traits are not going to be found in individual genes or environ-
ments. Attempting to do so results from misunderstanding those systems
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