The second element common to all temperament
characteristics is that these differences are inherent in
the person. Temperament is a biologically based re-
action to the world. This does not mean that all tem-
peramental differences are genetically inherited.
This is the foundation of Arnold Buss and Robert
Plomin’s EAS theory of temperament, with EAS
standing for the traits found to be heritable during in-
fancy (emotionality, activity, and sociability). Other
researchers, however, also include prenatal influ-
ences on children’s behavior. The idea that traits are
biologically based does not mean that these charac-
teristics are resistant to environmental influences. All
temperament theorists argue that social experiences
can and will change a child’s temperament. Inherent
simply means that these behavioral styles are not due
to parenting. Infants’ unique reactions to the world
have biological roots. For instance, many children
born to mothers addicted to drugs have very difficult
temperaments; these children cry often, are hard to
console, and do not like to be held. Their behavior is
thought to be due to the influence of the drugs on the
developing fetus in the womb. Other children may in-
herit from their parents a tendency to be emotional
or shy.
As early as 1699, the philosopher John Locke
maintained that children are born with different be-
havioral tendencies. He also believed that the envi-
ronment was the strongest force in development. To
Locke, social experiences, not temperamental differ-
ences, shaped behavior across development. This was
the predominant view of children’s development
until the 1960s and 1970s. During this time, Alexan-
der Thomas and Stella Chess published their classic
books about the role of temperament in parent-child
relationships and children’s social and emotional de-
velopment. Thomas and Chess argued that children’s
behavioral problems do not always stem from bad
parenting. Instead, some children come into this
world with temperament styles that make disciplining
them a challenge. Even competent, caring parents
may have difficult children and these parents need
help learning how to manage their sons and daugh-
ters.
Other child psychologists at this time also assert-
ed that children are born equipped with behavioral
biases and abilities that affect later development. The
cognitive psychologist Jean Piaget described infants
as active participants in their own experiences who
are motivated to learn how to adapt in their environ-
ments. By the end of the 1980s, the child was no lon-
ger seen as a piece of clay to be molded into an
obedient citizen, but as a force to be guided into a
competent adult. It was in this intellectual context
that the notion took hold that children are born with
unique temperament characteristics.
There is some evidence that early temperament traits predict
behavior in adolescence and adulthood. It is easier to predict the
future behavior of people with extreme temperament styles than of
those who fall in the middle. (Nathan Benn/Corbis)The third component of all definitions of temper-
ament is that behavioral styles are relatively stable
across development. Temperament characteristics
can and will change in response to parenting and
other social forces. The idea is that the early roots of
adult personality can be seen from the beginning.
Several studies have included groups of individuals
who were followed from birth to adulthood. The find-
ings from these studies regarding stability are mixed.
Children’s temperament traits do appear to be quite
stable through infancy and into childhood. Jerome
Kagan and his colleagues studied two extreme groups
of children from infancy to adolescence. Members of
the first group, behaviorally inhibited children, were
very shy and fearful in unfamiliar situations. Members
of the second group, behaviorally uninhibited chil-
dren, were very gregarious and assertive in novel set-
tings. The researchers found that the inhibited
children were at greater risk for later social and emo-TEMPERAMENT 409