Developmental psychology.pdf

Human Development 69
goslings that had been imprinted upon him and another group that had been imprinted
on the mother and placed them all together under a box. Lorenz stood nearby with the
goose, and as she moved away, he lifted the box and walked in a different direction.
The goslings imprinted upon Lorenz followed him; the others followed the goose (Lorenz,
1935, 1958).
Casual observation shows that a dog raised in a friendly manner from a tender
age becomes incurably attached to its caretaker. Adopted later, the dog may become
friendly but the attachment is never so firmly fixed. Similar behavior has been observed
among lambs, goats, deer, and other species (Sluckin, 1965; Bateson, 1966).*
Sensitive Periods In lower animals this early period of acute readiness to learn is
called a critical period, especially if the ensuing behavior is not readily altered. Their
exposure at this time to almost any relevant stimulus results in more permanent and
rapid learning than occurs later. As for the possibility of such periods in human
development, one investigator says that a child will not develop normally without "a
certain amount of attention and handling during a critical period of its infancy. This
period is doubtless not so sharply defined as imprinting in birds" (Hess, 1962).
Many researchers believe that there is an important early period for human
social responsiveness, but they do not speculate in regard to the exact interval. It is
probably unwise to assume a critical period when there may be different periods for
different responses (Hinde, 1963). The first three days after birth, for example, may
be sufficient for initiating infant bonding to the mother's voice (DeCasper & Fifer,
1980). Some investigators speak of a sensitive period, implying its importance but not
its irreversibility.
There is considerable evidence for this viewpoint, but inappropriate learning
during the early years is not always irreversible. The child's behavior at one year of
age might predict behavior months or even years later, but some problems observed
during the first few years eventually do diminish, presumably on account of the therapeutic
effects of subsequent experiences (Kagan, 1979).
It is indisputable, nevertheless, that the early environments are most important,
for in the first years one learns how to learn. Successes and failures tend to be
cumulative, as each outcome prepares the way for others. Early deficits are not easily
overcome. Whether they are temporary or lasting depends upon several factors, including
the severity of the deprivation, the time of onset, its duration, and the nature
of the ensuing stimulation (McCartney, 1984).
"When I was about seven years
old, I had a friend, Nik, who lived on
a farm in the country. It was Nik's
job to give bread to the geese at a
little pond, and we both found this
an excuse to remove ourselves
from the summer heat and feed the
birds from the water. We played at
being geese, and though our
attempts at diving were
unsuccessful, our honking
prospered. I remember finding
some eggs hidden in the bushes
near the water's edge. We checked
on them every afternoon until one
day we discovered that most of
them had hatched, and only a few
stragglers were still pecking away
at their shells. The mother was, as
usual, upset to see us near her
offspring, so we backed away. Nik
went to do the chores, but I
returned and honked at one funnylooking
gosling that apparently
couldn't decide whether it should
join the world or remain half in the
egg. My raucous persuasion finally
urged him out. I don't know how I
had the nerve, but I started to play
with him, talking softly, honking,
and gently stroking his sticky fuzz.
After a while I got tired, and when
Nik came back to find out if I'd like
to go wading, I forgot about my
new friend. Luckily, Nik noticed him
following us to the water, and from
then on I had a constant
companion. Specks wasn't
unfriendly to his mother or siblings;
he just didn't care much about
them.
COGNITIVE DEVELOPMENT
The third major area of human development, in addition to physical and social development,
is cognitive development. The term cognition means knowing or understanding,
and when we speak of cognitive development we are referring to mental development
in the broadest sense, including not only intelligence but also such complementary or
component processes as perceiving, recognizing, recalling, and interpreting information,
as well as all forms of reasoning. Cognition includes a wide range of human mental
abilities.
Within the area of cognitive psychology, perhaps the foremost figure in the
twentieth century has been Jean Piaget, an eminent Swiss epistemologist. His work,
conducted primarily through conversations and observations with his three children
and a nephew, concentrated upon the development of thought in the child.
Through these observations Piaget came to the view that the thinking of normal
children is not just a simpler version of the thinking of adults. It is qualitatively
different. It is based upon a different understanding of reality, one that slowly changes
according to maturation and experience. The sequence of these changes can be divided
into four periods or stages, approximately according to chronological age.