biological mechanism Case Study


Contributions of Neuroscience to Our Understanding of Cognitive Development Adele Diamond1 and Dima Amso2

1 Department of Psychiatry, University of British Columbia, and Department of Child and Adolescent Psychiatry,

BC Children’s Hospital, Vancouver, Canada; and 2 Sackler Institute for Developmental Psychobiology,

Weill Medical College of Cornell University

ABSTRACT—One major contribution of neuroscience to

understanding cognitive development has been in demon-

starting that biology is not destiny—that is, demonstrating

the remarkable role of experience in shaping the mind,

brain, and body. Only rarely has neuroscience provided

wholly new insights into cognitive development, but often

it has provided evidence of mechanisms by which obser-

vations of developmental psychologists could be explained.

Behavioral findings have often remained controversial

until an underlying biological mechanism for them was

offered. Neuroscience has demonstrated promise for de-

tecting cognitive problems before they are behaviorally

observable—and, hence, promise for early intervention. In

this article, we discuss examples drawn from imitation and

mirror neurons, phenylketonuria (PKU) and prefrontal

dopamine, maternal touch and stress reactivity, and non-

genetic (behavioral) intergenerational transmission of bi-

ological characteristics.

KEYWORDS—plasticity; epigenesis; mothering; executive

functions; animal models; molecular genetics; memory

Neuroscience research has made its greatest contributions to the

study of cognitive development by illuminating mechanisms

(providing a ‘‘how’’) that underlie behavioral observations made

earlier by psychologists. It has also made important contribu-

tions to our understanding of cognitive development by dem-

onstrating that the brain is far more plastic at all ages than

previously thought—and thus that the speed and extent by which

experience and behavior can shape the brain is greater than al-

most anyone imagined. In other words, rather than showing that

biology is destiny, neuroscience research has been at the fore-

front of demonstrating the powerful role of experience throughout

life. Besides the surprising evidence of the remarkable extent

of experience-induced plasticity, rarely has neuroscience given

us previously unknown insights into cognitive development, but

neuroscience does offer promise of being able to detect some

problems before they are behaviorally observable.




Here we describe two examples of behavioral findings by psy-

chologists that were largely ignored or extremely controversial

until underlying biological mechanisms capable of accounting

for them were provided by neuroscience research. One such

example concerns cognitive deficits documented in children

treated early and continuously for phenylketonuria (PKU). The

second example involves neonatal imitation observed by psy-

chologists and mirror neurons discovered by neuroscientists.

Prefrontal Dopamine System and PKU Cognitive Deficits

Since at least the mid-1980s, psychologists were reporting

cognitive deficits in children with PKU that resembled those

associated with frontal cortex dysfunction (e.g., Pennington,

VanDoornick, McCabe, & McCabe, 1985). Those reports did not

impact medical care, however. Doctors were skeptical. No one

could imagine a mechanism capable of producing what psy-

chologists claimed to be observing.