becoming an aggressive adult than does a child low in this temperament. But
parents who encourage problem-solving skills over the expression of angermay turn a highly emotional child into a cooperative, nonaggressive adult.
A child low in sociability is unlikely to become an outgoing, highly gregarious
adult, but that child might develop excellent social skills, be a wonderful
friend, and learn to lead others with a quiet, respectful style.
One reason general dispositions set the direction for adult personality
traits is that a child’ s disposition influences the type of environment he or
she lives in (Caspi, 1998; Rothbart & Ahadi, 1994). How other people react
to us, and whether they will be a part of our environment at all, is partly de-
termined by our temperament. Thus, children high in sociability are likely toseek out situations with other people. Parents react differently to a baby who
is constantly fussing and restless than to one who sleeps calmly. As a result,
the restless baby experiences a different parent-child relationship than chil-dren with other temperaments. Temperament also generates expectations in
other people that can affect the way they treat a child. Preschool teachers in
one study expected different personalities in the children in their classes basedon observations about the child’ s general activity level (Graziano, Jensen-
Campbell, & Sullivan-Logan, 1998). It is not hard to imagine that these dif-
ferent expectancies lead to different treatment.
In short, adult personalities are determined by both inherited tempera-
ment and the environment. Moreover, temperament influences the environ-ment, and the environment then influences the way temperament develops
into stable personality traits. Two children born with identical temperaments
can grow up to be two very different people. A child with a high activity level
may become an aggressive, achieving, or athletic adult. But that child will
probably not become lazy and indifferent. A child does not represent a blank
slate on which parents may draw whatever personality they desire. But nei-
ther is a child ’s personality set at birth, leaving the parents and society to set-
tle for whatever they get.
Inhibited and Uninhibited Children
Several decades ago, two developmental psychologists reported the results of
an investigation on personality tr ait stability (Kagan & Moss, 1962). They
had measured traits when the participants were 2 or 3 years old and again
when these same people were 20. Although most traits showed at least a
little change over time, one appeared remarkably stable. The researchers
found that children who were passive and cautious when faced with a newsituation usually grew up to be adults who showed a similar pattern of shy-
ness around strangers. Because envir onmental explanations of behavior
were prevalent at the time, the researchers assumed this stable trait was the
result of some type of “acquired fearfulness ”shaped by the parents during
childhood.
Today those psychologists have a different interpretation. They argue that
these different styles are the result of inherited dispositions (Kagan, 2003; Kagan &
Snidman, 2004). Moreover, they find that approximately 10% of Caucasian
American children fall into a category they refer to as “inhibited ”(Kagan &232 CHAPTER 9 The Biological Approach