BRAIN X EXPERIENCE

This account of early brain development emphasizes the ways in which
the nervous system is designed to recruit and incorporate experience into its
developing architecture and neurochemistry. Normal experience (e.g., good
nutrition, patterned visual information) supports normal brain development,
and abnormal experience (e.g., prenatal alcohol exposure, occluded
vision) can cause abnormal neural and behavioral development (Black et
al., 1998). Plasticity is a double-edged sword that leads to both adaptation
and vulnerability. The process of synaptic overproduction and loss is dependent
on environmental information, although the evidence is largely
restricted to sensory systems. Similarly, the brain’s neurochemistry is exquisitely
sensitive to behavioral and environmental stimuli. Scientists are
far, however, from linking specific types or amounts of experience to the
developing structure or neurochemistry of the immature human brain, and,
conversely, from understanding how early brain development affects the
ways in which young children process the abundance of information and
experiences that their environments present to them. Answers to questions
about when during development particular experiences must occur and
when, in fact, timing is important and when it is not also lie, to a large
extent, beyond the boundaries of current knowledge. Research on the
developing brain can nevertheless provide a framework for considering the
effects of early experience on development more generally. The questions
that have been asked by neuroscientists have their parallels in research on
behavioral development.