In public-health studies comparing different
populations or countries, the percentage of young
children with very short stature (stunting) and the
percentage of those whose weight is very low for how
tall they are (wasting) are important indicators of nu-
tritional and health conditions affecting children. In
such studies, the average age at menarche, or of other
maturational events, may be used to indicate the ade-
quacy of general health and nutritional conditions.
Some examples of the average age at menarche
from different countries are given in Table 1. Average
ages of menarche greater than 13.5 years are usually
considered to be associated with some general nutri-
tional or health constraints in the country. In the case
of Nepal, these issues are probably complicated by the
people living at very high altitude, which may affect
growth and maturation because of the reduced avail-
ability of oxygen to the body.
When nutritional energy (calories from food) is in
excess of what the body uses and what is expended in
physical activity, it is stored in adipose tissue. This fat
tissue is accumulated within the body and subcutane-
ously (under the skin). The growth in weight of chil-
dren and measurements of the thickness of the
subcutaneous fat by calipers are used as indicators of
overweight and obesity. Sometimes the weight of chil-
dren is expressed as an index relative to stature (cal-
culated by dividing the weight, in kilograms, by the
square of stature, in meters) to yield the body mass
index (BMI). BMI standards are also commonly used
to define overweight and obesity and to relate these
conditions to various health outcomes.
Physical growth includes many aspects of the bio-
logical development of children that can reflect ge-
netics, nutrition, health, and the environment. The
aspects of physical growth are central to the child’s
progress toward adulthood, and they inevitably inter-
act with psychological, behavioral, and social aspects
of the developing child.
TABLE 1 See also: MENARCHE; MILESTONES OF
DEVELOPMENT; MOTOR DEVELOPMENT;
NUTRITION; OBESITY
Bibliography
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Malina, Robert M., and Claude Bouchard. Growth, Maturation, and
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John H. Himes
LaVell GoldPIAGET, JEAN (1896–1980)
Jean Piaget’s scientific career began at the age of elev-
en with the publication of a brief notice on an albino
sparrow and lasted nearly seventy-five years, resulting
in more than sixty books and five hundred articles.
Although often referred to as a child psychologist,
Piaget was trained as a zoologist and considered him-
self an epistemologist (a person who studies the na-
ture and development of knowledge). Piaget’s
fascination with children’s reasoning began with his
work on early Intelligence Quotient (IQ) tests when
he noticed that children’s errors were systematic and
followed a logic that was entirely different from that
used by adults. Systematic observation of his own chil-
dren and ingenious experiments and interviews with
thousands of children and adolescents led Piaget to
propose that knowledge develops in a series of stages.
Each stage is marked by particular forms of thought
that are constructed by the child through interaction
with the world. This theory of stages coupled with Pia-
get’s insistence that children play an active role in
their own cognitive development had a profound im-
pact on the field of education. Rather than viewing
children as empty vessels to be filled with collections
of facts, educators came to appreciate that children
construct knowledge much like scientists do, by test-
ing their ideas in action and by modifying their
knowledge in response to environmental feedback. In
a very real way, children produce their own develop-
ment.
The roots of Piaget’s theorizing can be seen in his
autobiographical novel, Recherche, published in 1918308 PIAGET, JEAN