Genes, Brains, and Human Potential The Science and Ideology of Intelligence

186 HOW THE BRAIN MAKES POTENTIAL

Th is interpretation is supported in other ways. It has been known for
de cades that actual light experience is impor tant for development of func-
tional connectivity in the visual system. But recent studies show that it
is patterned (i.e., spatiotemporally structured) light that is crucial. Con-
fi ning visual experience to “white light” (i.e., presenting all light frequencies
without the patterned quality) actually retards development of connectiv-
ity in the visual cortex. Th is prerequisite also seems to apply in the audi-
tory system: exposure to white (uniform) sound during early development
seems to severely disrupt connectivity formation.^21 Although the brain is
sometimes referred to as “data hungry,” in real ity it is “pattern hungry.”
Far from being a blank slate, therefore, it is geared up for the abstraction
of informational structure from experience; that structure is not predeter-
mined by genes.
Multisensory integration is crucial for maximizing information from
the environment, as noted above. But it, too, develops according to expe-
rience. Th is was shown in studies by Barry Stein and colleagues. Th eir
studies showed that “neurons in a newborn’s brain are not capable of multi-
sensory integration... the development of this pro cess is not predeter-

dendrite

terminals

nerve cell

body

axon

terminals

FIGURE 6.2

Getting connected. Axon terminals, guided by molecular signals, fi nd target cells.

Th ere, development of dendrite terminals is promoted by structured spike fi ring along

the axons.

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