Early Development: From Creation to Adolescence
Early Development -
PSYCHOLOGY: Exploring Behavior
Chapter 3: Early Development: From Creation to Adolescence
Early Development: From Creation To Adolescence
Goals of Developmental Psychologists
Methods of Developmental Psychologists
What is Development?
Physical Environment and Development
Social Environment Within the Family
Social Environment Beyond the Family
The Interaction of Heredity and environment
Development and Forms of Behavior
How about humans?
Genetics, Dominance and Recession
Changes in Infancy
Motor skills in Infancy
Sensing the World in Infancy
Language development in Infancy
Self-concept in Infancy
Childhood Changes: Skills and Body
USING PSYCHOLOGY: Psychology and Parenting
Language Development in Childhood
Self-Concept in Childhood
INTERESTED IN MORE?
Early Development: From Creation to Adolescence
WHAT'S THE ANSWER?: From Conception to Confusion
"Last summer I served as a senior counselor in a summer
camp up at the lake. Late one evening I was writing a letter to
my girl friend when the biggest spider I've ever seen dropped
into view. I decided to play a dirty trick on him. The spider
was weaving the circular part of his web, so I unhooked that
first strand from the porch floor and part of the web shriveled
up. You know what that spider did? He started all over again!
-- when all he had to do was anchor one more support and go
right on." Why did the spider start its web from the beginning?
"Marcia's parents both have brown eyes," she said.
"That's not possible," he said. "Marcia has blue eyes!
Brown-eyed parents can't have blue-eyed children."Who's right?
He or she?
"My sister and brother-in-law had a baby girl about a month
ago. Last night when I was playing with their baby I put my
index fingers in her hands. When I moved my fingers, she didn't
let go. In fact, I lifted her right up off the blanket! My
sister was there to catch her if anything had happened. But I
really don't understand it. That baby can't even hold her own
bottle, but she's strong enough to hold herself up in mid-air!"
What did happen here?
Developmental psychologists study changes in human behavior
as they relate to age -- ranging from developmental changes in
the early years to those of adolescence, adulthood and our
retirement years. Most studies observing developmental changes
in human behavior are trying to describe the behavior and to
explain it -- the ultimate goals of developmental psychologists.
The usual research techniques offer partial solutions to
problems caused by the changing environments of youth during the
past century. To control this problem developmental
psychologists use methods such as longitudinal and crosssectional
studies, taking care to select groups at each age that
are as comparable as possible.
Maturation involves changes in behavior due to
physiological growth. Development includes all changes in
behavior related to aging. There are two major groups of
factors that influence our behavior. One is the heredity. The
other source is environment, which provides a certain range of
experiences. Our physical environment and social environment --
both within the family and beyond the family -- combine with
hereditary factors to influence our behavior. Ultimately our
behavior is determined by the interaction of heredity and
From studying animals, psychologists have identified a
number of forms of behavior, ranging from simple to complex.
Ethologists have identified a number of processes in animal
behavior that also apply to humans. These include taxis,
reflexes, and instinctive responses as well as more complex
responses based on learning and reasoning. Maturation and
development proceed in humans in definite sequences. Human
behavior changes from mass-action toward differentiation, and
from simple toward more complex.
Concerning human development DNA-carrying genes combine to
convey dominant and recessive characteristics to the new
organism. During the prenatal period, a mother may unknowingly
injure the neonate or fetus by ingesting certain substances.
The fetus can already react to stimuli which come from outside
its mother. The process of birth seldom causes any damage to
During the first two years of life a baby is considered an
infant. During this time humans experience one of their most
rapid periods of change in body size and proportion, and motor
skills develop quite rapidly. Although possessing a wide range
of functional sensory organs, the infant gains much skill in
interpreting incoming messages. Hand preference begins to
develop, and the infant learns to stand and walk. Meanwhile,
starting from random emission of sounds and progressing through
babbling, telegraphic speech, and the error of overgeneralization,
the infant's language develops (even by age one)
begins to communicate with a clearly developing self-concept.
During childhood, which stretches roughly from two to
twelve years of age, a child experiences a moderate amount of
body growth and increases in motor skills. Significant motor
skill is gained both in motor coordination and in accomplishing
more and more refined tasks; strength, reaction time, and
balance also improve. Knowledge of a child's developing body
and skills is especially helpful in fulfilling one's role as a
parent. During early childhood language develops with the
remaining classes of words being mastered. During the latter
half of childhood, vocabulary size is increased. The selfconcept
undergoes marked development. Social experiences in
playing with peers help children learn acceptable ways to
The Review Questions will help with mastery of the
materials covered in this chapter. After reading the chapter
you may be interested in trying some of the suggested
ACTIVITIES. Further information about selected topics within
this chapter is available in follow-up readings suggested in the
INTERESTED IN MORE? section.
Especially in the study of early development --
particularly before children's language is well developed --
psychologists emphasize the observation of behavior. Suppose
you're waiting for a bus. At the bus stop with you are a very
heavy woman, burdened with packages, and a mother with her twoyear-
old daughter. When the bus arrives with standing room
only, the child pipes up loudly "Is that fat lady going to get
in the bus?" Although the mother is no doubt embarrassed,
probably neither you nor any of the other adults are surprised
by the child's tactless question. You attribute it to the youth
of the child.
Suppose you're waiting for
a bus. This time waiting with
you are the heavyset woman and
a woman accompanied by her
twenty-two-year old daughter.
When the crowded bus arrives,
the daughter asks loudly "Is
that fat lady going to get on
the bus?" How do you react?
You probably look shocked. You
expect a person of that age
to keep her thoughts to herself or even offer to help the
burdened woman. You attribute the 22-year-old's remark to
uncontrolled, antisocial behavior.
Now suppose you're waiting for the bus, but this time
waiting with you and the heavyset woman are an eighty-two-yearold
woman and her daughter. When the crowded bus pulls up, the
elderly woman asks, "Is that fat person going to get on the
bus?" What is your reaction? You are probably tolerant of the
outspoken old woman. You may understand that she could feel
threatened at the thought of being crushed in the crowd and is
unable to conceal her anxiety. You may even attribute her
remark to her senility.
From this simple example we can note several points about
(1) We all constantly observe the behavior of those around
(2) We often base our own reactions to others on very
(3) We often make assumptions about other human beings
based on these limited observations.
In all three scenes at the bus stop, only one independent
variable differs: the age of the person speaking. Yet your
behavior, the dependent variable, probably differs in each case.
Your reactions demonstrate that as humans age, the behavior
expected of us changes. What is appropriate behavior at one age
is inappropriate at another.
That's the essence of developmental psychology: the study
of human behavior as it relates to age. Developmental
psychologists are concerned with the lawfulness, or
predictability, of human behavior. With enough scientific
information about a person, they try to predict how a person
will behave at certain ages and in certain situations. This
leads us to examine the goals and methods of developmental
Goals of Developmental Psychologists
In the context of observing behavior, the earliest studies
of age-related changes in human behavior date back 2,000 years
or more. For many years it has been recognized that both
heredity and environment influence how we develop. Yet, only
since the 1930's or so have we begun to make real progress in
our understanding. All of the earliest studies of human
behavior were descriptive.
Scientists observed behavior as it occurred and then
described it precisely. These illustrations, for example, are
only descriptive. They are based on careful observation of
changes occurring as an infant begins to coordinate muscles and,
eventually, to walk. Today, developmental psychologists seek
not only to describe behavior but also to explain it -- a far
more difficult goal. Psychologists do this by trying to
identify the important independent variables that influence
changes in our behavior as we grow older. Watch carefully as
you read within this chapter. See if you can identify for
yourself when a behavior is being described and when it is being
If you think about it, you'll realize that when studying
developmental changes, the presence of age as a "nuisance"
variable is inevitable. Older people didn't grow up in the same
environment as younger ones. For example, first, it is likely
your grandparents didn't eat
food of the same quality and
variety that you do. They
probably had poorer schooling
and fewer medications with
which to treat diseases.
Second, you are likely to be
better educated at your age
today than your grandparents
were when they were your age.
Our system of education is better, and more sources of
knowledge-from e-mail to television to the Discovery channel-are
readily available. In short, the environment of many elderly
people during their childhood was probably not as good as the
typical environment of most children or adolescents today. So
if a psychologist found in a study that older people differed
from young people, what was the cause? Age? Or was it the
different environments of childhood? We've got a confounding
variable here. Controlling for confounding variables in studies
of development is usually accomplished in one of two ways, using
either a longitudinal or a cross-sectional study -- both
examined in the methods of developmental psychologists.
Methods of Developmental Psychologists
Pursuing the goals of developmental psychologists who are
interested in observing behavior of infants and children as they
age, one of two research methods is frequently used. One way to
collect data is to observe one group of participants over a long
period of time. Perhaps you might repeat your measurements at
regular intervals. This is
called a longitudinal study.
It does allow us to study the
effects of early factors on
later behavior. It also
gives us good control over
such things as intelligence
and personality when we draw
our original samples. But
there are also problems here.
Any errors in selecting our
participants at the start remain in the data for the entire
experiment. Thus, the sample and design of a longitudinal study
are no more sophisticated than psychology is at the time the
sample is established. Moreover, such experiments take a long
time to conduct. Psychologists age just as rapidly as anyone
else. As described in the Appendix, longitudinal studies use a
within-participants design. It almost seems that the only way a
good longitudinal study can be conducted is for a young
psychologist to have a good idea for an experiment early in his
or her career!
Another way to gather data is to conduct a cross-sectional
study. This involves a one-time-only period during which two or
more groups of different age are observed. In such a study we
would usually use the same measures for each group. Obviously,
such studies have some advantages. The time to conduct the
study is usually quite short. And the findings are likely to be
more immediately useful. As described in the Appendix,
longitudinal studies use a between-participants design. We
wouldn't conduct such a study if we didn't have a need to answer
questions that are important right now.
Yet, there are also difficulties. Any time you try to
compare groups of people who differ in age, you have a very
complex problem. Trying to choose participants for each group
who are similar is not easy. The problem, as we discussed
elsewhere, is controlling all the confounding variables.
There's another problem. One of the phenomena discussed in
our treatment of long-term memory is flashbulb memories. Each
group of people who are generally the same age are called a
cohort. Their life experiences are more similar to one
another's than they are to those of a different age. One major
difference is the flashbulb memories they retain -- events so
startling that we remember not only the event but where we were,
who we were with, and what we were doing when we first learned
of an event. For people in their late 50's or early 60's, their
usual flashbulb memory is the assassination of President John F.
Kennedy in November 1963. For those in their 20's, a frequently
cited flashbulb memory is the Challenger disaster. Each age has
a different cumulative experience as they mature; likely, this
influences their beliefs, their behaviors. The effects of
differing cohort experiences confounds comparisons across
differing age participants.
In addition, we may not be able to study the effects of
early experience on later behavior. Why? Because recordkeeping
was not always good in years gone by; therefore the only
record of what happened to our parents and -- especially -- our
grandparents is often their own memory. Memory is helpful,
except for some problems we discuss in the Remembering chapter.
However, you wouldn't let a player for the Washington Redskins
serve as referee in an NFL contest between the Redskins and the
Dallas Cowboys, would you? For the same reasons, we are each
poor observers of the events influencing our own lives. We are
not impartial. Using longitudinal and cross-sectional research
techniques, developmental psychologists can begin to identify
what influences our development.
Think About It
The question: If you and your parents and their parents all graduate(d)
from high school at the top of their (your) class, who will know the most:
You? Your parents? Your grandparents?
The answer: You should now know enough to understand that this is a very
hard question to answer. It's neither a cross-sectional nor a longitudinal
study: The age of the people involved is different, yes, but the quality of
the schooling received by each of you is also different. What if we were
able to give a test of knowledge to you at graduation, as well as to your
parents and grandparents when they had graduated? We'd still have the problem
of the differing quality of schooling. Who's smarter? In some ways, that's
almost impossible to answer.
What is Development?
The methods of developmental psychology have been applied
to increase our understanding of developmental processes which
influence almost everything psychologists study -- from seeing
to talking, from eating to sleeping. Here -- whether studying
early development in infancy and childhood, or development from
adolescence through death -- we are discussing development from
what is called a life-span approach. And our discussion of
developmental processes at each age is limited mainly to four
areas: (1) physical changes or growth, (2) motor and sensory
development, or changes in performance skills, (3) development
of language, and (4) development of the self-concept, which
includes an awareness of things such as emotions, intelligence,
and social skills. What is development?
Development refers to
the changes in behavioral and
organisms experience as they
live. Though this may involve
either gaining or losing
abilities or qualities, it
systematic change, as we'll
see. Development should be
contrasted with maturation, which involves only those changes in
behavior that can be directly traced to physical growth.
Learning to ride a bike or to drive a car provides a good
example of the difference between maturation and development.
To master control of a bike or car you must be big enough
physically to handle the controls and developed enough
personally and socially to appreciate the responsibilities that
are involved. Development refers to qualitative aspects of your
behavior; maturation refers to quantitative aspects such as the
state of your body and its readiness for a behavior.
There are two major groups of factors that influence human
behavior: heredity and environment which registers its effects
in several ways, including effects of our physical environment
and our social environment both within the family and beyond the
family. These hereditary and environmental factors also
interact to produce specific effects in any one of us.
Now, before we look at the effects of hereditary factors,
let's clarify some issues. First, the environment in which we
live has a direct influence on both our behavior and our
development. Any child raised by a family that is abusive, or
that fails to meet the child's needs, is more likely to have
psychological problems. Such a child is less likely as an adult
to be as well-adjusted than is one raised in a family that is
loving and responsive. Different environments cause different
changes in behavior. The quality in human beings that allows
such changes to take place is called malleability.
But then there's heredity to consider. There are limits to
how much we can change anyone's environment and expect it to
show up in his or her behavior. To be malleable does not mean
that all individuals raised in the same environment will develop
identical skills. Think a moment. If a fire occurred at a
party, some of your friends would be too scared to move. Others
would scream. Some would act to put out the fire; others would
rush for the exits. And the same is true of most situations in
which we humans may find ourselves. Some of us are active, some
passive; some happy, some sad; some tall, some short; some
smart, some not so smart. Part of what accounts for these
differences is inherited capabilities.
Unfortunately, many people think about inherited
characteristics only in terms of simple things such as eye
color. We all know that no amount of practice is going to turn
blue eyes into brown. But many people also assume that any
characteristic that is inherited -- or known to be genetically
caused -- can't be changed. They assume an inherited
characteristic isn't subject to the whims and changes of the
environment. That's not so. It is important to realize that
genes do not define your behavior absolutely. At best your
genes create what some psychologists have called a "range of
possible experiences." Your environment, then, determines what
your actual experience will be.
Across the entirety of
developmental processes which
impact our behavior, the
primary hereditary factors
are two kinds of inherited
"information." One is
general information which
yields humans or dogs or
giraffes as the information
dictates. The other is
specific information. It
passes on patterns that cause
you to mature into a being who can be identified as part of your
own family. Such patterns include your hair and eye color, your
skin tone, the shape of your hand and head and body. But the
specific information also includes more complex factors such as
your general level of excitability, your intellectual potential,
and even certain aspects of your personality.
Many things determine how we study the impact of heredity.
There are values such as religion, morals, and love which
prohibit using humans in research on the effects of heredity.
In addition to these ethical issues, there is a practical one:
If humans were studied, the experimenter would be outlived
before his or her participants had had a chance to demonstrate
all their behaviors! For these reasons, to understand hereditary
influences, scientists have turned their attention to other
living things -- including plants and animals.
One of the most frequently used techniques for studying
inherited characteristics is the process of selective breeding.
The work of Gregor Mendel was the original in this area. Mendel
worked with the garden pea, but the basic principles he
developed have since been applied to both humans and animals.
These same techniques have also been applied to the study of
Feature 3.1 presents one of the classic studies of
selective breeding of animals. As you can see from this study
of rats, one procedure involves selecting two animals to breed,
both of whom are good examples of whatever trait is being
studied. The breeding is then used to "purify" that
PARDON ME, YOUR BREEDING IS SHOWING
In the late 1920's one psychologist gathered up 142 rats.
In addition to reducing the local rat population, this also
yielded a random sample of local rats. The psychologist had all
142 rats run through a maze from start to finish 19 times. If
they reached the correct goal box, they earned a piece of
cheese. For all 19 trials the number of errors each rat made
was recorded. As you might suspect, the rats performed better
with practice. In fact, some rats ran more than half the trials
without making any wrong turns at all.
When the experiment was done, the average performance of
all the rats was plotted, as you can see in Figure (a). In this
random sample the total number of errors in 19 trials ranged
from 9 to 214. Some of the rats making the least number of
errors—called the "maze- bright" rats—were selected to mate. In
addition, some of the rats that made a lot of errors learning
the maze were selected for breeding. These were
called—surprise—the "maze-dull" rats.
All of the children (they're called progeny) of the
maze-bright and maze-dull rats then tried to learn the same maze
in 19 trials, the errors again being recorded. The same
procedure was repeated through eight generations. Each time
only the brightest and the dullest of a generation were bred to
produce the next generation—bright breeding with bright and dull
Figure b shows the performance of the third generation—the
grandchildren. Notice that already the performance of the
progeny of the brightest rats is beginning to separate from that
of the progeny of the dullest rats. And Figure c shows the
performance results from the progeny of the eighth generation.
By now the maze-bright rats' performance is so good that it
almost doesn't even overlap with that of the maze-dull rats.
What these rats demonstrated, of course, was that it was
possible to breed for behavioral characteristics. This was
among the first times this was demonstrated in the laboratory.
But don't be misled. Don't assume the maze-bright rats in this
experiment were bright in everything they attempted. Far from
it. Another psychologist took the eighth generation rats and
put them in a similar, deeper, water-filled alley where they had
to swim. Here you could not distinguish their performance from
the maze-dull rats in the previous experiments. So, although
the experiment produced rats that were very "bright" in one kind
of experiment, it did not produce a breed of Albert Einsteinlike
In the study of inherited factors in human behavior, two
techniques are most frequently used. One is the study of twins.
Here we can examine the similarities and differences in the
behavior of two humans. We know more about the genetic
information than we would about any two people selected at
random. Identical twins are created from a single fertilized
egg -- of which we'll talk elsewhere in this chapter. Their
heredity is identical. Fraternal -- non-identical -- twins are
created from two separately fertilized eggs. We can compare
identical and fraternal twins who have been raised together or
separately -- as might happen if twins are separated shortly
after birth and raised in adopted or foster homes.
Such studies have suggested that inherited factors do seem
to influence intelligence, some personality characteristics,
susceptibility to schizophrenia (which we discuss in the chapter
on behavioral disorders), as well as shared interests and
attitudes toward authority. There are, of course, a number of
problems in isolating the effects of environmental factors from
those of inherited factors. These problems are well-illustrated
in the other technique which has been used to study the
influence of heredity on human behavior -- the family tree.
Look at the family tree illustrated in this Figure. This
shows seven generations of the ancestors and later relations, or
progeny, of Johann Sebastian Bach, one of the most famous
classical musician/composers ever to live. From this technique
of study, called genotyping, you can see, from 50 to almost 90
percent of the people related to J. S. Bach in each generation
gained the main part of their livelihood through music --
playing it, writing it, or conducting it.
Yet, there's a problem. Are we to credit this love of and
predominance in music to heredity or environment? If it's true
that to be a classical pianist you need a finger span from the
tip of your little finger to the end of thumb that will cover 13
white keys on the piano keyboard, then perhaps we should argue
that heredity was the critical factor. But don't you suppose
the children of J. S. Bach heard good music in their home? And
don't you suppose that the Bach children -- if they showed any
skill in music -- would've been encouraged, maybe even forced,
into musical activities? In the absence of records, we'll never
know. So separating the influence of heredity and environment
isn't always easy. We have more to say about this elsewhere in
this chapter. You should have detected, however, that our
environment -- both our physical environment and our social
environment within our family and beyond our family -- also
impacts our development.
Physical Environment and Development
Clearly, our heredity
impacts our development, yet
just as obviously, so does
our environment. In
analyzing the role of the
environment in influencing
our development, we've got a
problem. Deciding exactly
what qualifies as an
is a bit hard to do. In one sense, environmental influences
include everything that is not inherited. Perhaps the best way
to simplify this problem is to distinguish between physical and
social environmental factors -- both within the family and
Up until birth, your physical environment literally
surrounds you. It surrounds you more loosely after birth, but
there are still a number of important influences. These
include, first, the ecological factors surrounding you, such as
the quality and the temperature of the air you breathe. Under
certain conditions sound can be a stressor; those who camp do
not go to the woods or the shore to listen to someone else's
choice of boombox music. Residents of buildings near major
highways, airports, or rail lines may experience stressful
amounts of noise.
A second physical factor
is the food you eat. Our
diet now is generally better
than in the preceding
decades, yet it's far from
perfect. For example, a
battle has long raged about
whether saccharin does/does
not cause cancer. If it
does, how much does it take
to make the danger of getting cancer something worth worrying
Food additives -- for color, for flavor -- may also
influence the quality of our food. And, surprisingly, whether
or not we cook our food and how we do it may end up subtracting
from the raw food elements that would be good for us. Vitamins
and some nutrients can be lost in the processes of manufacturing
and cooking certain foods.
Third and finally,
chemicals are a very
important contributor to our
physical environment. As
discussed in more detail in
the Chapter dealing with
physiological processes, some
drugs serve only to "pollute"
our body with chemicals that
can be dangerous in large
amounts. Each of these factors in our physical environment is
an important influence in our lives.
Social Environment Within the Family
In addition to factors in our physical environment which
influence our development, there is another, completely
different source of environmental influence. Your social
environment is made up first of family members. Later, friends
and role models beyond or outside your family are added. Their
relative contribution depends directly on your age and the
restrictiveness of your parents. Let's look at some social
factors within the family.
Within the social environment created by a traditional
family, one or more of three elements may be important: your
mother, your father, and your siblings (brothers and sisters),
with the possibility that other relatives may also live with and
influence you. Your parents play several important roles
(detailed in the Chapter discussing Social Behavior in Groups).
Parents usually provide financial support and supply the emotion
(love) that ties a family together. They also teach cultural
values: It's not nice to litter. You should respect proper
authority. Be honest. Finish any job you start. Brush your
teeth twice a day. You know what these "cultural values" are!
But your parents also play a major role in shaping your
personality. They reward you for getting up on time. They
instill good (or bad) manners in you. They influence your views
of members of other races, communities, and nations. In short,
they shaped a lot of the values you held at least up through
high school. (We discuss in the Chapter covering from puberty
through old age how some of this early training changes once you
leave your parents' home.) Finally, your parents also decide
(and enforce?) who does what jobs and when -- very important
decisions if a family is to operate effectively.
Now, while these are things your parents share, there are
also some marked differences in the roles played by your mother
and by your father. Some contributions are almost always made
only by one or the other.
There are also the
social contributions made by
your siblings. We'll discuss
their importance in more
detail in the Chapter
discussing social behavior in
groups, but notice your
siblings do have an impact on
at least your childhood and
The social environment within your family is most important
until you enter elementary school. From that time on, an
increasing proportion of the social factors influencing your
development come from outside or beyond the family group.
Social Environment Beyond the Family
Of the major sources of
influences beyond the home
which impact our development,
arguably the most powerful is
television. One source
suggests that the average
high school graduate of the
80's had spent more time in
front of a television set
than in a classroom since entering first grade. The influence
of television is probably even stronger today. And what are the
effects of that much television viewing? The catharsis theory
suggests that watching aggressive acts on television reduces the
likelihood a person will act aggressively. By contrast, the
social learning theory suggests that if children learn by
watching, then seeing acts of aggression on television should
increase a child's aggression rather than lessen it.
A report summarizing a decade of research on the effects of
television was released by the National Institute of Mental
Health in 1982. It concluded that violence on television does
lead to aggressive behavior by children. Researchers are only
beginning to study whether television also influences children's
thought and emotional processes. Can children's social beliefs,
behavior, and relationships -- even their health -- be
influenced by television? Pressure to smoke is greatest in
junior high school. Can television be used to blunt those
pressures? All sorts of possibilities abound.
A second social factor
beyond the family, obviously,
is school. Schools are
intended mainly to achieve
two purposes. One is to
teach the intellectual skills
that citizens will need to
succeed in society. These
are the old "readin',
writin', and 'rithmetic."
They are the means to communicate the content of society's
progress so far.
There is less agreement about the other purpose. Many
people feel that school should improve a student's self-esteem.
It should provide opportunities for and guidance in developing
social skills. It should, in short, help students learn about
how to live and enjoy life, how to play, how to think logically,
and how to enjoy esthetic beauty, whether that be art or music.
The relative emphasis to be placed on "the three R's" and social
skills tends to be controversial.
A third major source of
influence beyond the family
affecting the behavior of
children and adolescents is
the peer group. That is the
friends and schoolmates of
generally the same age. It
may be the child next door, a
boy- or girl-friend, or just
members of one's classes in
school. The influence of the peer group doesn't really develop
until school age, but it becomes extremely powerful during high
school years. Many parents worry about their children's choice
of friends. What parents (and you, for that matter) may not
know is that most children and youths tend to choose friends of
whom their parents would approve anyway.
Another social factor, which was more directly controlled
by your parents when you were in high school, is the degree to
which your peer group will have influence over you. This tends
to be in inverse proportion to the amount of influence your
parents exercise. If your social, emotional, and other needs
are met by your parents, you will have less need in high school
to turn to your peers for support, for experience, for anything.
Beginning with college, parents are essentially replaced as a
major source of influence by the peer groups.
Recent research has revealed a final point. Some
psychologists have noticed that peer groups serve as "levelers."
Such groups provide a low-threat means for you to find out
whether the training you've received at home works correctly
"out in the real world." If your parents are too conservative,
your friends are likely to seem wild to your parents. If your
family life is quite liberal, your friends may perceive you as a
So the combination of friends (and foes), family, school,
and television educates you in the ways of the world. Some
psychologists talk of hereditary and environmental influences as
separate, but equal, but are they? Others argue in favor of an
interaction between heredity and environment.
The Interaction of Heredity and Environment
As discussed in the Chapter on the Nature and Nurture of
Psychology, the old nature-nurture argument is often posed as an
either-or kind of debate, but it isn't. Rather, it should be
concerned with "how much of each?" In the behaviors of interest
to psychologists, your inheritance (nature; your genetic
structure) sets a range of possible responses that you might
achieve. The environment(nurture) can provide a range of
possible experiences, but yours will be a particular
environment. What occurs in each of us is a reaction uniquely
determined by our heredity to the particular environment in
which we find ourselves.
Some feel that we tend to consider ourselves passive lumps
of clay, moldable in any way by the environment to which we are
exposed. Actually, we play a vital role in choosing our own
environments. We often select environments that we like and
reject those that we dislike.
Look at the Figure to
see what can happen if we
combine nature and nurture in
one specific example. Suppose
your genes had given you a
large frame -- big bones and
a stocky build. Think about
the different effects that
environments offering (1) too
little, (2) adequate, or (3)
(3) too much food would have on your body. Now compare the
impact of these same food conditions if the original genetic
message had been to create a small frame for you -- small bones
and a slight build. What is the difference between a
genetically stocky frame raised in a food-poor environment and a
genetically slight frame raised in a food-rich environment? The
differences tend to disappear, don't they? Both heredity and
environment influence biological and psychological factors.
Moreover, heredity and environment -- both within and
beyond the family -- interact in another complex way to
determine how we develop. For the sake of argument, let's
assert that the introversion you experience [a tendency to seek
quiet environments, to prefer small (or no!) groups] is
hereditary. If so, you would be genetically guided toward
selecting environments in which an introvert would be
comfortable. As an adult, you'd likely be an introvert. But,
at what point does your repeated exposure to the introvert's
favorite environment itself -- as an environmental factor! --
begin to influence your choice of environments? Certainly, you
gain more experience with introvert-comfortable environments,
less with other environments. At what point does your selection
of environments become environmentally governed? Separating the
relative contributions of heredity and environment as well as
the interaction between them can become very complex.
Heredity has demonstrable effects on our behavior; as does
our environment. Most interestingly, the interaction of
heredity with a specific environment leads to very complex
Development and Forms of Behavior
The study of development, including the relative influences
on development of heredity and environment to our behavior, has
involved a wide variety of research techniques. Some of the
facts about human development were first suggested from the
study of animals and the forms of behavior which they exhibit.
In studying the range of animal behaviors -- from the
simplest one-celled amoebae to the most complex multi-celled
primates and humans -- one thing becomes obvious. As you
progress from simple to sophisticated organisms in the animal
world, you also move from automatic to rational, controlled
patterns of behavior. Let's look at five such forms of behavior
starting with the simplest.
A taxis (pronounced
TACK-sis) involves the
response or orientation of a
whole animal either toward or
away from some physical
stimulus. We humans have a
negative geotaxis. That
means that we orient
ourselves away from the pull
of gravity. In short, we
A reflex is an unlearned
response to a stimulus.
However, unlike the taxic
response, which involves the
whole organism, a reflex
usually does not. If you've
ever visited a doctor's
office, more than likely your
doctor has tested your kneejerk
reflex by tapping your
knee gently with a rubber mallet. Your foot responds
involuntarily by kicking upward. This is the knee-jerk reflex.
A third form of behavior
is the instinct. An instinct
is a complex pattern of
response that is unlearned
and present in all normal
members of a species. Unlike
reflexes, which are fairly
simple, instinctive responses
may last for some time after
the stimulus that initiates
The last two forms of response will be mentioned here in
our discussion of early development, from creation to
adolescence, but we spend whole chapters discussing them
elsewhere. One is learning, which we'll define for now simply
as instances where experience modifies or alters behavior. If
you start salivating every time you smell lasagna, that's an
example of learning. The other and most complex form of
behavior is reasoning. This involves the use of abstract
symbols, such as a written language or a system of numbers.
Using such a system to solve problems, communicate, or educate
illustrates the use of reasoning. An example? How many words
can be made from the letters in TEXAS? Answering that question
As you move up the
hierarchy of animals, you
find more and more reliance
on higher response forms and
less and less reliance on
simple, automatic responses.
For the simplest animals,
such as protozoa, all
responses are automatic. At
the other end of the scale,
our human behavior involves only a very few taxic responses. We
have a few reflexes and instincts, but we rely strongly on
learning and reasoning for most of our behavior.
Think about it
The question: The summer camp counselor we quoted at the start of the
chapter was surprised to find that the spider he interrupted started
web-building from the very beginning again. Are you?
The answer:You shouldn't be. Weaving a spider web is an instinctive
response. The spiral weaving response is probably set off by the existence
of the main supports of the web. When the web lacks those main supports, the
spider starts again by first spinning the main supports for his web.
Development and the
forms of behavior which
evolve have been studied from
a variety of perspectives.
One unusual view involves
with work of biologists
interested in identifying the
underlying human and,
especially, animal behavior -
the work of ethologists. The lessons of ethology also apply to
Among the most skillful studies of development of animals'
behavior has been the work of the ethologists which has evolved
out of the work of biologists. Ethologists are zoologists who
apply the principles of naturalistic observation to the study of
animals' behavior in their natural environment. Work of this
kind was so good, so new, and so challenging that three of the
first ethologists earned the Nobel Prize in 1973 for their
contributions -- work which has implications for human behavior.
The photograph shows a
number of greylag geese
following ethologist Konrad
Lorenz. In fact, they have
imprinted on him, a process
that involves an interesting
combination of learning and
maturation. There are three
necessary elements in
imprinting. These elements
are timing, the presence of an object to be imprinted on, and
young organisms at the particular age of imprinting. It happens
in many animals, but especially in birds.
When birds hatch, the first living, moving object they see
is usually their mother. They imprint on her and will follow
her anywhere. But what if birds are raised in an incubator, and
the first moving object they see is a decoy? If this happens,
the birds will imprint on the decoy. In fact, the farther those
birds have to follow the decoy, the stronger will be the
imprinting that results. In Lorenz' case, he had been the first
thing the goslings had seen.
It has been suggested that imprinting takes place during a
time interval limited by (1) an increasing fear of strange
objects, and (2) a decreasing inclination to approach anything
that moves or attracts attention. The combined effects of these
two processes yields what is called a critical period. It is a
period of time during which the events that will cause
imprinting must occur if it is to result. Early enthusiasm
surrounding the discovery of the imprinting process lead
investigators to think that once the birds were imprinted to a
decoy (as the goslings were to Lorenz), the process couldn't be
reversed. Not so.
More recent work has shown that imprinting on an incorrect
object is less stable than if an organism imprinted correctly.
Ducks imprinted to humans -- when later exposed to their own
mother for a period of time -- will stay with her rather than
returning to the person on whom they had originally been
imprinted. Surprisingly, this work also has implications for
How About Humans?
The work of the
ethologists has focused
primarily on the development
of specific forms of animal
behavior. Are there critical
periods in humans? The
evidence so far suggests that
we do have critical periods -
- perhaps quite a number of
them -- during which we need
certain kinds of experiences.
We need exposure to other
humans in order to learn to speak and to learn various social
skills during the early years of infancy and most of childhood.
And we need the handling, attention, and care of a mother or
father in the earliest years of infancy. People denied these
opportunities seem to suffer from slow learning of the missing
skills when the opportunity finally presents itself -- if they
are able to learn the needed skills at all. Clearly, delaying
some experiences beyond these ill-defined "critical periods" can
have damaging effects.
A final concept,
important to both humans and
animals, is that of
maturational readiness. This
identifies the first time an
organism is physically ready
and able to respond correctly
in a particular situation.
With humans, for instance,
there has long been an
argument as to the best time
at which to start training a youngster to read. Certainly, many
children started at the age of three or four can do very well if
given constant attention. Yet others not trained at all until
the age of six or so seem to catch up quite quickly. Purely as
a matter of efficiency, is it necessary to start children as
soon as they can hold a book up? Apparently not. It seems that
the point of maturational readiness to learn to read is reached
when a child -- no matter how old he or she actually is -- can
do what the average five to five-and-one-half-year-old can do.
The illustration describes in some detail how principles of
maturation operate in all humans in definite, predictable
sequences. You might also refer to where we show the various
stages taking place as children learn to walk as another example
of maturational readiness.
Based on the development of techniques for study of
developmental and maturational changes, another question becomes
of interest. What developments take place within the individual
human from the time he or she is conceived through infancy and
childhood to adolescence? In this Chapter on Early Development
and the Chapter on Development: Adolescence to Death we talk
about many events in normal development, starting with
procreation, continuing through when the first word is spoken,
when an infant can stand and walk, and so forth. The figures we
cite and the graphs and figures show average figures, or norms.
Knowing a norm is like
knowing the average shoe size
of an army: It's
descriptive, but useless in
equipping personnel. Keep in
mind that there are wide
variations among humans in
the rate at which they mature
and develop. The process
starts with human procreation
and -- still within mother's
womb -- includes prenatal life. Our discussion includes changes
in infancy, including body changes, motor skills, and how we
interact with our world as infants. We also look at changes in
language development in infancy as well as in childhood, and we
discuss our evolving self-concept both in infancy and childhood.
We summarize the major changes in childhood skills and body and
look at how a knowledge of psychology can help with parenting.
Genetics, Dominance and Recession
As you already know from biology courses, the process of
procreation in humans begins when the sperm from a male unites
with the egg of a female to start the development of a new
human. The chromosomes within the fertilized human egg (or
zygote) are composed of bead-like strands called genes. Genes
contain the genetic code. This code is the order in which
molecules transmit genetic information, or all the
characteristics that are passed on through the generations. It
has been estimated that there may be 10,000 to 50,000 genes in
each fertilized egg!
The genetic code itself
is embodied within structures
of DNA, or deoxyribonucleic
acid. The DNA is the master
key determining the genetic
portion of the physique and
the potential behavior of
every soon-to-be-born infant.
Each of us was created by a
mixing of many genetic
messages -- about hair, skin, and eye color, about physique and
abilities, about everything -- at the moment of procreation.
However, we do not result from a mixing of our parents'
characteristics as when you mix paint. Let's say the genetic
codes of a man and a woman have been combined. What happens if
one message says "blue eyes" and the other says "brown eyes"? A
dominant gene, such as the gene for brown eyes, exerts its full
effect over the effect of a recessive gene, such as the gene for
blue eyes. Thus, any mixed genetic message will be expressed in
the individual child in accordance with the dominant gene. The
effect of a recessive gene will be expressed only if paired with
another recessive gene. Our bodies or abilities may show the
effects of a dominant gene even while we carry recessive traits
and may transmit them to our children.
The theory suggests that we, the carriers, do not influence
the genes we carry. We simply pass them on to our children.
The Bach children whom we discussed earlier may well have become
interested in piano through their parents' interest. But they
could not know how to play a Bach concerto through a genetic
message. They had to learn. And thus the human embryo is
launched on its prenatal life.
Think about it
The question: Well, what's your verdict? Can brown-eyed parents have
The answer: Yes. You can construct a table as follows, where B = brown
(the dominant eye color) and b = blue (the recessive eye color). In short,
if Marcia's parents are both of the Bb type themselves (with brown eyes but
carrying recessive blue genes), the chances are that 25 percent of their
children would have blue eyes (bb). As for the others, 25 percent would have
brown eyes (BB), and 50 percent would have brown but be carrying recessive
blue genes (Bb).
B BB Bb
b Bb bb
determined by genetics, the
maturation of the human
zygote, later embryo, is
generally most susceptible to
the effects of a poor
environment during the first
three months (called a
trimester) of growth
following procreation. As
organs and life systems
mature, there may be times when some pollutants have a higher
than normal likelihood of causing certain abnormalities.
Diseases, drugs, and various medical treatments, such as x-rays,
may have bad effects. Poor eating habits of a mother-to-be take
their worst toll during this time. Unfortunately, a woman may
not be aware that she is pregnant during this critical first
During the last
trimester the fetus is
already beginning to react to
events outside its mother.
One researcher placed a small
block of wood over the
abdomen of mothers in the
latter part of the eighth
month. When these
researchers hit the board lightly with something that emitted a
loud noise, about 90 percent of the fetuses began squirming
excitedly and kicking. (See Table 3.1 for a definition of this
and other terms we'll be using.)
Ages and stages for children
AGE NAME STAGE
0-2 weeks* Zygote Germinal phase
2-8 weeks* Embryo Embryonic phase
2-9 months* Fetus Fetal period
0-2 years Infant Infancy
2-7 years Child Early childhood
7-12 years Child Late childhood
12-20 Teenager Adolescence
*Age from conception.
Even before birth fetuses show vast individual differences.
Ask any woman who has had two or more children -- babies differ
tremendously. Some fetuses may be active 75 percent of the
time, others only 5 percent. Some pregnant women have even
reported they preferred not to go to symphony concerts -- their
babies responded to the music and applause with violent
squirming! So the evidence is more and more clear-cut that
fetuses can and do respond to environmental stimulation even
Another thought may have occurred to you. Does the mental
state of the mother during pregnancy affect the baby before and
after it is born? Obviously when any of us get upset, our body
chemistry changes. If we are afraid, our adrenal glands pump
actively, while our digestive processes stop. And if we're sad
or angry? Happy or delirious? The answers here are less easy
to provide. One study has been done of the babies delivered to
mothers who were suddenly faced with an extreme fear or grief
(as in the loss of the father) or anxiety during their last
trimester of pregnancy. Generally the unborn fetuses of such
mothers tended to show marked increases in their activity -- as
much as a tenfold increase sometimes -- at the time of the
shock. After birth these infants were mentally and physically
all right, but they tended to be unusually irritable and very
active. Some even had feeding problems.
And how about drugs? Women who smoke a lot tend to give
birth to smaller and lighter infants. Infants born to mothers
addicted to narcotics or alcohol tend to show the same severe
withdrawal symptoms their mothers would if they stopped taking
the narcotic. On the other hand, there are benefits to this
blood-linked communication from mother to fetus. Mothers'
immunities to diseases such as mumps, measles, whooping cough,
and scarlet fever are passed on to the newborn child.
During the birthing process itself, only one kind of injury
is likely to occur. This is brain damage caused by the use of
forceps (instruments used to aid delivery) or a shortage of
oxygen as the baby shifts from the mother to the environment
outside. Such difficulties, however, rarely occur.
An interesting theory has gained ground in the past several
decades about birth being a major psychological trauma. It's an
appealing idea. Leaving a warm environment that was established
and designed to meet the infant's every need would seem to be a
foolish thing to do by adult standards. But remember the
dangers of anthropomorphism -- attributing thoughts and motives,
and complex ones at that, where none may exist. Suffice to say,
there is no evidence currently available that the birthing
process itself is a traumatic event. It has not been shown that
birth serves as the source of serious personality problems that
may develop later in life.
At this point our maturing human is ready to enter infancy,
the final step into childhood.
Changes in Infancy
Infancy -- roughly from birth to age two -- involves
massive body changes, major improvements in motor skills
including handedness and how we sense the world. Language
development leads to significant improvement in self expression
which ultimately leads to evolving changes in an infant's selfconcept.
Changes in an infant's body size that occur between
birth and age two are extensive. Growth is rapid during the
first year of human life. By the end of the first year, an
infant triples his or her birth weight and stretches out from a
starting length of 48-53 cm (19-21 inches) to a height of 63-74
cm. (25-29 inches).
There are a number of problems psychologists face when
studying infant development. For one thing, early physical
factors such as the size, agility, and sensing factors, as well
as early intellectual abilities, are of no use in predicting a
person's childhood and adult levels of such factors. A baby's
length and weight at birth, for example, don't allow us to
predict his or her adult height or weight. Also, there is the
difficulty of knowing how to pose a research "question" so an
infant will pay attention long enough to give us an
interpretable answer! By the time a child is two, however, we
can begin to make a few predictions with ever-greater accuracy.
Consider growth rate, for example, which slows down a bit
during the second year. Even so, by his or her second birthday
a child may well reach a quarter of the ideal (note, we did not
say actual) adult weight. And the average two-year-old will be
almost half as tall as he or she will be as an adult. Major
changes also occur in an infant's motor skills.
Motor Skills in Infancy
One of the most intriguing things about a newborn infant is
that despite the significant body changes which occur, a wide
range of responses have already been "pre-wired." These response
patterns -- some of them quite complex -- show up as reflexes.
A motor skill that is always a worry to parents is the
development of handedness -- shall he or she be right- or lefthanded?
World-wide, only about five percent of humans are lefthanded,
but a clear preference doesn't really develop until the
latter part of the infant's first year. Even well into the
second year an infant will still experiment a great deal -- now
eating with the right hand, now with the left, and sometimes
Exactly why we develop a preference for one hand over the
other is not clear. It may result from which side of our brain
is dominant, called cerebral dominance, which we discuss in the
Chapter on Physiological Processes. But it's clear that society
as a whole is set up for right-handers. Everything from school
desks to scissors, from hand-shaking to vegetable peelers, is
designed for right-handers. Is this a cause of righthandedness,
or does it result because of right-handedness? It
was the fashion in the past to encourage infants to become
right-handed at all costs. The best procedure now is thought to
be to let handedness develop on its own. It saves worry and
wear and tear on parents, teachers and left-handed children as
Think about it
The question: Remember the four-week-old baby girl who suspended herself
in mid-air by simply hanging on to two extended adult fingers? Can this be
The answer: Yes. It's called the grasping reflex. It's present in only
about 40 percent of all infants, and it disappears completely by the end of
the third month.
Sensing the World in Infancy
When infants arrive in
this world they already have
some rather well-developed
sensory skills for detecting
parts of their environment.
Yet, we know that an infant's
reactions to the world about
him or her are directly
related to whether the infant
is sleepy or alert, quiet or
crying. The best time for
studying infants is when they are alert, but quiet -- which
makes the task a bit difficult with newborns since they sleep
most of the time. It has been learned that infants are less
alert when they are flat on their backs. In that position they
tend to fall asleep. It's interesting that our modern chairs
for holding infants while they're being fed tend to position the
infants on an incline. Perhaps this same finding regarding the
influence of the incline is why infants stop crying when they
are picked up and put over their father's or mother's shoulder.
The smells, sounds, and other things in the world around them
now catch their attention.
Yet, many other things also influence an infant. Too hot,
and the infant will fall asleep; too cold, and it will cry.
Tightly wrapped, infants tend to go to sleep; left naked, they
tend to cry. Too bright, and they shut their eyes; too dim, and
they'll go to sleep. Too loud, and they cry; yet with just a
calm background noise (remember the use of music boxes?), they
fall asleep. So finding out what an infant can do when
attentive is no easy task!
In spite of this, accompanying developing motor skills,
there is significant improvement in an infant's skill in sensing
the world. Psychologists have learned that shortly after birth
an infant is already more likely to look at a human face than at
a random collection of the same number of features, as discussed
in Feature 3.2 We know from this that infants can see shortly
after birth. Yet, other work has shown that the focal point of
an infant's vision is only about nine inches away from his or
her face. Interestingly, that's about the distance many women
hold their infants from their own face when nursing them.
WHAT DO INFANTS SEE?
When we make statements that an infant can do this or can't
do that, a problem must have occurred to you. How can we find
out what an infant too young to tell us can actually do and see
and hear? When infants start crawling, can they detect when
they've reached the edge of a staircase? In fact, let's take a
specific problem that was important to each of us: Can infants
recognize a human face? Can they see at all?
We do know that infants can detect and respond to
differences in brightness and motion when they are not even one
day old. They prefer, in their first weeks, to look at the
edges of stimuli—as if they are learning first the shapes of
stimuli. But how about a face? Can an infant detect the
difference between a face and an equally complex figure that is
just a number of scrambled parts?
To answer this question, the four forms in the illustration
were shown to a number of four-month-old infants. Several
findings are immediately apparent when we examine what
proportion of the total viewing time was spent looking at each
First, the most normal human face drew the most attention.
Second, the form with the fewest details drew the least
attention. Third, when choosing between two forms of equal
complexity (Faces b and d ), infants gazed longer at Face b.
This suggests that the meaning of the form—the face in this
instance—may be more important in attracting and holding an
infant's attention than the complexity. All this was learned
just by showing some infants some forms and watching what they
How about hearing? Elsewhere in this chapter we discuss
fetuses who become very active if a loud noise is produced
outside their mother's womb. Shortly after birth an infant can
be trained to turn his or her head toward a bell if food is
given when the infant does so. When held upright between
parents who are both speaking to him or her, the infant will
turn more often toward the mother, perhaps because the mother is
already the more familiar person.
If a change in its environment is detected by an alert
infant, several things tend to happen. Its level of activity
increases, and its heart rate and pattern of breathing change.
We can use this to find out what infants can detect. For
example, we now know that infants can smell even within two days
after birth. First we get them used to smells ranging from
acetic acid (a much less concentrated version of which exists in
citrus fruits) to anise (which is like licorice). Then, if one
of those smells is changed and that change is detected, what do
we find? Right. The activity level, heart rate, and breathing
all change. Taste, as we'll see in the Chapter discussing
Sensation and Perception, is not as sensitive as smell, yet
infants can even distinguish between their mother's milk and a
cow's milk! Paralleling these improvements in motor skills and
sensory skills, the infant's language development undergoes
substantial change in the first two years -- from speechlessness
to limited loquaciousness.
Language Development in Infancy
During infancy it seems
that factors of physiological
growth and maturation play a
large role in the language
skills that develop. This is
suggested by several things:
First, the initial steps
through the first couple of
years of language development
are remarkably similar worldwide:
The same sounds appear
first, everywhere. There is
the same sequence of increasing linguistic complexity and the
same order of use and purpose of word classes. Second, infants
have a knack for language. It would be an incredible feat to
learn enough to be communicating as effectively as two-year-olds
do in only two years. By that age a child has usually achieved
a vocabulary of at least 300-400 words, and some psycholinguists
argue the size is closer to 1,800-2,000 words! The first count
of the number of words known and used by children was done more
than half a century ago -- in 1926. At that time six-year-olds
were estimated to know about 2,500 words. The widespread use of
television and radio in modern society makes it likely that this
figure is a serious underestimate for youth today. One
psycholinguist has estimated a child learns ten new words a day
from 18 months to 5 years of age. That would mean a 5-year-old
could easily have a vocabulary of 13,000-15,000 words!
However, not all psychologists share the same opinion about
how language develops. It is an area rich with arguments these
days because views are changing rapidly. At birth you had only
two choices: You could cry or be quiet. Yet by the time you
were four weeks old you were already beginning to "say"
different things. When you were uncomfortable, you got tense.
As a result your vocal cords were more constricted and narrow.
The nature of your crying changed. When you were happy, your
vocal cords were more relaxed and you emitted a more open, backof-
the mouth sound. It may be just an accident of muscle
control, but parents can read these cues. Even as a four-weekold
infant you were beginning to "speak."
At three months you reached the babbling stage. It seems
to be enjoyable since infants all over the world do it. We emit
random sounds, and we do a lot of it between three and six
months of age. In the last half of the first year (6 to 12
months) two things begin to happen. First, infants begin to
show repetitive syllabification, which means they say the same
syllables over and over again. It's in this stage that most
proud parents proclaim that they hear their infant's first
"word." But who's to say when repeating ma-ma-ma-ma-ma-ma or papa-
papa-pa-pa changes to "ma-ma" or "pa-pa"? Nevertheless it
does occur somewhere around the start of the second year, and
who's to argue with proud parents?
The other process occurring in the last half of the first
year is imitation. Infants are natural mimics. Listen to a
six- to twelve-month-old infant, and you'll hear it mimicking
many different sounds in its world -- some verbal, some not.
But during this period the sounds being emitted are getting more
and more sophisticated. "Foreign" sounds -- meaning those not
used to vocalize the language the infant is about to learn --
begin to disappear. A one year-old will react to verbal
stimuli, and he or she will react very differently to angry and
During the next six months (12 to 18 months) there is a
steady increase in the number and variety and complexity of
sounds being emitted. One-word utterances occur more and more
often. They're mostly nouns. In the last part of infancy (18
to 24 months) single-word utterances become two-word phrases.
At this stage two processes can be heard. One is the
development of telegraphic speech. "Mommy milk!" may mean
anything from "Mother, I would like to drink some milk." to
"Mother, your elbow just knocked a one-gallon container of lowfat,
homogenized and very expensive milk onto the floor." In
short, the important words are there, but none of the
The other process that is heard is over-generalization.
Infants try to apply simple rules in complex situations. They
may learn that -ed means past tense, but then they apply that
rule to too many verbs: "Daddy goed," "Mommy eated," and so
forth. It's a mistake, but it's a good mistake, for it shows
the infant is thinking about language. He or she is beginning
to try to develop and apply the rules that will govern the use
of this new-found skill called talking. The increasing
complexity of language development aids the infant's developing
The Self-concept in Infancy
One of the most fascinating things to watch as it develops
during infancy is the changing, shifting view of self. Self is
a very hard concept to define -- even more so for an infant.
One way is to define self as anything you can touch that will
result in two experiences of touch. (Touch your arm with your
finger, for example. Your arm will feel the pressure of your
finger; your finger will feel the warmth of your arm.) Feature
3.3 describes one major source that helps an infant develop a
Crying is a very selfish thing that infants do. Almost
everything else is socially oriented somehow: babbling, staring
at you, smiling at you—even imitating you. But crying is very
self-centered. Yet, as with so many things an infant does, the
results produced by crying also teach the infant something about
his or her world.
The way a parent responds to crying influences the
attachment that forms between parents and their child.
Attachment is the bond of affection that exists between an
infant and other individuals—most often the mother and father.
One psychologist studied the patterns of behavior that existed
between 26 mothers and their children. We're going to look only
at the most extreme cases in that study.
For example, suppose you were a parent in the following
situation; what would you do? Your child is crying—apparently
for food—but you've just fed it an hour ago. Would you yield to
its needs and feed it again? Or would you consider your own
needs and feed it on a schedule? What kind of an attachment
would result when either the infant's needs dominate or the
mother's needs dominate? We will find some rather surprising
First, with a year-old infant, letting the baby's needs
predominate led to a better interaction between mother and
child—yes, a better interaction. Subsequently, when it was put
down by the mother and apparently deserted, the infant whose
needs had been met as they developed instead of according to the
parent's schedule, cried less.
So how are we to explain this? The major factor here seems
to be the trust developed by the infant. If it was repeatedly
left to cry, it learned that the world was not to be trusted,
that its needs would not be met as they arose. On the other
hand, infants whose cries were followed by having their needs
met, were learning that the world can be trusted. They learned
that mother (or father) was a trustworthy person, that that
person would show up as needs arose. The result was that by
responding to a child's cries during the early months of its
life, these parents created a more trusting infant. The more
trusting infants eventually cried less, were more tolerant of
frustration, and offered a richer variety of communications.
But what are the tasks of the infant here? Table 3.2 lists
the components of self-hood that develop during infancy. Perhaps
the second task there best shows the difficulty in defining
self. For the first several months of its life an infant
doesn't distinguish between itself and the environment of which
it is a part. There is no boundary between itself and the
world. Understanding that boundary is but one of the tasks in
developing the sense of self.
An infant's tasks in self-concept development
Infancy 1) Identify self as able to cause events.
(0-24 months) 2) Awareness of boundaries and shape of body.
3) Awareness of viscera; events (such as a stomach ache).
4) Recognition of self (as in a mirror).
5) Recognition of self as a constant in a world offering
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All this while, from birth to two, the infant is testing
and probing its environment. One theorist ( whose work
is discussed in more detail elsewhere in this Chapter and that
dealing with Development: From Puberty to Old Age) has suggested
one major task at this age is to form a view of the world -- of
either basic trust or mistrust. Another is to begin to develop
a sense of self-control. Once these tasks have been mastered,
the infant is ready to enter childhood.
Skills and Body
Upon concluding the
major experiences of infancy,
the maturing human moves into
the events of childhood.
What happens along the way
from childhood to
adolescence? What changes take place, physically and mentally?
(As you read about the evolving skills of childhood, be sure to
keep in mind our caution about the limits of norms: They're
helpful in identifying an average, but not in describing an
individual.) These changes involve continuing increases in the
complexity of motor skills of which a child is capable, and
substantial body changes. Language development continues to
show increasing complexity and size of vocabulary, and the selfconcept
moves away from self-centered to reflect increasing
awareness of others.
What skills can you expect young children to perform? In
terms of motor skills, two-year-olds are able to walk with an
even rhythm, and they can put on their own shoes, but they can't
hop on one foot. Their drawing skill is limited to imitating
vertical and horizontal lines. Three-year-olds can walk a line
on the floor, but their drawings are usually just scribbles. A
four year-old can hop on one foot but often only one, walk on a
balance beam, and draw crude figures of humans and other
objects. By five a child can hop on either foot, tie his or her
shoelaces, and draw identifiable animals, houses, and so forth.
From six to twelve a child is mainly involved in a general
improvement of motor performance. Dancing or tumbling classes
are beneficial in giving the child practice in more and more
refined motor skills. The child will notice a steady increase
in his or her strength, reaction time, and balance.
You have probably noticed that when you learn any new motor
skill, you must at first pay a lot of attention to its
perceptual, or mental, aspects. In learning to play any musical
instrument, you must concentrate on where your fingers are and
how what your fingers are doing is related to what you hear.
Mastering any motor skill involves first integrating all the
incoming information from your eyes, your hands -- in fact, all
your senses. Then you practice until you have succeeded in
moving control of the new skill from the conscious to the
unconscious realm. For example, once a person knows how to
roller skate, he or she no longer thinks about it. But compare
that performance with that of a five-year-old just learning how
to maintain balance, see where to go, lean, turn, and brake all
at the same time! The USING PSYCHOLOGY section illustrates how
the cumulative contributions of changing body size and
increasing motor skills impact that most basic of childhood
activities -- play.
The basic senses work quite well in the two-year-old. What
continues to develop, however, is the more complex uses to which
sensory information is put. For instance, one aspect of this
development is cross-modal transfer. Suppose we showed you the
objects drawn in the Figure. We then put them in a bag and
asked you to pick out, without looking, the red object. If you
came up with the right object, you would be performing a crossmodal
transfer. This means that you'd have taken incoming
visual stimuli and translated them, interpreting the same object
in terms of touch. As children grow older, these complex skills
are constantly improving -- but of course at different rates for
There are two final
facts that you should note
about body changes and motor
abilities in children
approaching puberty. First,
as the quality and general
availability of both food and
medical services keep
improving in North America,
children keep maturing at
earlier and earlier ages. Second, the age of twelve (roughly)
marks the point of greatest difference in the relative
maturation of boys and girls. At this time girls are from 18-24
months ahead of boys in the percentage of their adult form they
have achieved! One area where there is sharing is in the
complexity of language development each human exhibits in late
Using Psychology: Psychology and Parenting
Even people too young or
too old to be biological
parents are sometimes put in
the position where they must
care for young children. Do
you have younger brothers or
sisters? Have you been a
camp counselor or a "baby"
sitter? If so, knowing a
little about what to expect
and how to amuse children at different ages may be of help.
Since we cover in some detail most stages of development --
both physical and mental -- in this chapter, here we only
concern ourselves with play. Various studies have indicated
that "child's play" isn't the simple thing the phrase implies.
In fact, there's a definite progression in play behavior.
Basically, children play games that get more and more
complex as they get older. Knowing about that progression will
help you in entertaining children for whom you must provide
care. Six forms of play have been identified.
Unoccupied behavior is the first kind of child-controlled
behavior we observe. An infant will simply examine his or her
own body or look around the room. For you sitters, this can be
the easiest "minding" job of all. An environment with
interesting (familiar!) things to see, hear, or manipulate can
keep a baby happy. Remember the fascination of the human face
for an infant.
Onlooker play seems to show an awakening awareness that
other children exist. The child talks with other children who
are playing -- may even make suggestions or ask questions -- but
does not get into the action. Watching will usually be quite
satisfactory for such a child.
Solitary play involves a two- to three-year old child
playing with toys all by him- or herself. None of the actions
the child makes are influenced at all by what other nearby
children are doing. Now, combining familiar and interesting
toys with isolated observing will keep a child happy -- still
assuming that all bodily needs for food and so forth are met!
Parallel play involves children playing with the same toys,
but not really interacting with each other. They will be
playing beside, but not with, each other. This form is at its
peak in two- to three-year-olds. By this age a child
appreciates having a friend around, even though he or she may be
doing the same thing separately.
Associative play involves the sharing of materials, and
some shared interacting behaviors. Here children have similar,
but not necessarily identical, goals. This form of play starts
to show up in four-year-olds, and by five the younger forms of
play are not seen very often. Now group projects with plenty of
materials for everyone will be a hit -- all painting separate
pictures, for instance.
Cooperative, organized play is the last to occur. Now
there is a single activity using the same materials and a
common, accepted set of rules. Children play many different
roles here. The key now is to have an interesting, challenging
game with rules.
There is a surprising footnote to these findings. The
study that identified these styles of play in the 1930's was
repeated in the early 70's. Four decades after the original
study, North American youngsters were not engaging in as many
socially oriented forms of play. Certainly the last two forms
of play tended to occur later than they did half a century ago.
Can this be caused by too much television viewing? It's an
interesting question to ponder.
Language Development in Childhood
You will recall that when we left our developing two-yearold,
he/she had achieved a vocabulary of at least 300-400 words
at the beginning of childhood, and some would argue the
vocabulary may have reached 1,800-2,000 words. The trends that
start in infancy continue into early childhood. During the
third and fourth year many more word classes make their first
appearance. A vocabulary that had only nouns and verbs grows
rapidly to include adjectives, adverbs, prepositions, and even
pronouns -- the last major class to be mastered. During the
fifth and sixth year children simply gain more sophistication in
their language. Some psychologists would argue that by the age
of five to six a child knows all of the formal elements of
his/her language. The only skills important to the use of that
language which continue to develop well past the age of twelve
are the size of the vocabulary and the complexity of the
However, one interesting skill does develop between five
and twelve -- the ability to use language to talk about
language. That's a skill that is uniquely human, as we discuss
at some length in Chapters on Learning and Language. This
improving language is accompanied by continuing alterations of
the child's self-concept.
Self-Concept in Childhood
An evolving aspect of children's personality is their selfconcept.
Table 3.3 lists the many and varied events that
influence a child's self-concept as he or she progresses through
Years two through 12. These factors are divided into those
experienced in early and late childhood. There are marked
differences in the concerns for and about the self of young
children as compared to those of older ones.
In terms of the theory of Erikson, there are several tasks
for the child to master between these ages. The child continues
to gain knowledge about self control and begins to separate himor
her-self from mother, without feelings of guilt. Other major
tasks of childhood are to develop the conscience and to begin to
form a sex-role identity.
As these tasks are encountered, the developing language
begins to be used as an aid. You'll hear a marked increase in
"what" and "why" questions as the child ingests more and more
information. There is an awakening awareness of the differences
between boys and girls, and this too is explored.
A child's tasks in self-concept development*
Early Childhood 1). Identify internal moods.
(2- 7 years) 2). Awareness of self as an object analyzed by others
("Isn't he cute?" "Isn't she smart?")
3). View of self as willful, internally controlled ("let
me do it!")
4). Self as part of family, friendship groups.
5). Self as a sexual person, fitting certain sex-roles.
6). Self as a moral person with goals for an ideal self.
7). Self as (non-) initiator of events.
Late Childhood 1). Physical changes leading to revision of body image.
(8-12 years) 2). Development and evaluation of skills.
3). Appreciation of multiple- roles for self.
*Adapted from Newman and Newman, 1978.
So far the family has been the major learning ground, but
the last major task of childhood is accomplished mainly in
school. It is to develop a sense of industry -- the ability and
desire to do things and do them well. Both parents and teachers
encourage this skill by achieving a careful blend of challenges
to keep the child thinking positively even if experiencing some
So, at this point we have a fully developed child, ready --
to the extent anyone is -- for adolescence. In adolescence that
child's world -- almost mastered -- turns topsy-turvy again as
he/she enters puberty.
Review Questions For Developmental
1. What do developmental psychologists?
2. As used by psychologists, what is meant by "lawfulness
GOALS AND METHODS OF DEVELOPMENTAL PSYCHOLOGY
1. What are some of the problems involved in studying
2. What are the experimental methods used to avoid the
Early Development - Chapter 3 106
PSYCHOLOGY: Exploring Behavior
WHAT INFLUENCES DEVELOPMENT?
1. How does development differ from maturation?
2. What are the major factors influencing our behavior?
Give examples of each.
THE STUDY OF DEVELOPMENT
1. What behaviors have psychologists identified by
2. Define critical periods and maturational readiness. Do
these concepts apply to animals or humans or both?
TOWARD THE STUDY OF HUMANS
1. What sequences are followed in the maturation and
development of humans?
2. What purposes do genes serve?
3. To what environmental influences is a fetus sensitive?
1. In the normal human life span, when is the period of
2. Name some important motor skills developed in infancy.
3. Trace the sequence of human speech development in
4. According to Erikson's theory, what attitudes toward
world are developed in infancy?
1. What ages does childhood include?
2. What motor skills develop during childhood?
3. How does the use of language develop during childhood?
4. What changes in self-concept occur during childhood?
Early Development Activities
1. According to Piaget's theory, during its first eight
months an infant learns that objects have "permanence." That is,
objects continue to exist even when hidden from one's view. If
you can find an infant who is less than eight months old, try to
determine whether the child has yet mastered this concept.
Place a toy in front of the child where the child can see it.
Then cover the toy completely with a towel. What does the
infant do? Infants under four months of age rarely pay much
attention. Infants from four to eight months will look at the
towel but probably not under it. Some infants might duplicate
the feat of most eight-month-olds and search under the towel.
What did your test subject do?
2. To test the maturity of a child's motor skills, see if
you can find a two-, a three-, a four-, and a five-year-old.
Ask each child to hop up and down on one leg. What happens?
Can a child who can hop on one foot hop on the other? Practice
will do very little good until a certain point of maturational
readiness has been reached.
3. Career Search. Volunteer to spend some time in a daycare
center. Record your observations about children's
behavior, being sure to record their ages, too. Which
principles of maturation and development might explain what you
saw? Discuss your observations with w fellow student or your
4. At a playground or day-care center listen to the talk
of two- to four-year-old children. How does their grammar
differ from yours? Did you hear them use telegraphic speech or
commit any errors of over-generalization?
5. To gain an understanding of children's abilities and
limits in thinking, interview a number of children of different
ages. You might ask a classic question such as "How does the
sun get from where it goes down (in the West) to where it comes
up (in the East)?" In analyzing the answers, compare the
underlying logic of the children of different ages.
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