398 Part IV Dispositional Theories
Postulates for Characteristic Adaptations
The postulate concerning characteristic adaptations states that, over time, people
adapt to their environment “by acquiring patterns of thoughts, feelings, and behav-
iors that are consistent with their personality traits and earlier adaptations” (McCrae
& Costa, 2003, p. 190). In other words, traits affect the way we adapt to the
changes in our environment. Moreover, our basic tendencies result in our seeking
and selecting particular environments that match our dispositions. For instance, an
extraverted person may join a dance club, whereas an assertive person may become
a lawyer or business executive.
The second characteristic adaptation postulate—maladjustment—suggests
that our responses are not always consistent with personal goals or cultural values.
For example, when introversion is carried to an extreme, it may result in patho-
logical social shyness, which prevents people from going out of the house or
holding down a job. Also, aggression carried to an extreme may lead to belliger-
ence and antagonism, which then result in being frequently fired from jobs. These
habits, attitudes, and competencies that make up characteristic adaptations some-
times become so rigid or compulsive that they become maladaptive.
The third characteristic adaptation postulate states that basic traits may
“change over time in response to biological maturation, changes in the environ-
ment, or deliberate interventions” (McCrae & Costa, 2003, p. 190). This is McCrae
and Costa’s plasticity postulate, one that recognizes that although basic tendencies
may be rather stable over the lifetime, characteristic adaptations are not. For exam-
ple, interventions such as psychotherapy and behavior modification may have a
difficult time changing a person’s fundamental traits, but they may be potent
enough to alter a person’s characteristic responses.Related Research
The trait approach taken by Robert McCrae and Paul Costa is very popular in the
field of personality. Costa and McCrae have developed a widely used personality
inventory, namely the NEO-PI (Costa & McCrae, 1985, 1992).
Traits have been linked to vital outcomes such as physical health (Martin,
Friedman, & Schwartz, 2007), well-being (Costa & McCrae, 1980), and academic
success (Noftle & Robins, 2007; Zyphur, Islam, & Landis, 2007); but traits have
also been linked to more common, everyday outcomes such as mood (McNiel &
Fleeson, 2006). As seen below, traits can predict long-term outcomes like GPA
(Noftle & Robins, 2007) that are the product of years of work, but traits can also
predict more discrete outcomes like whether personality predicts Internet usage
among teenagers (van der Aa et al., 2009), and what kind of mood you might be
in on any given day (McNiel & Fleeson, 2006).Personality and Academic Performance
Personality traits are strong predictors of many aspects of life. One area that
has received a fair amount of research is the relationship between traits and
academic performance, as measured by standardized test scores and GPA.
Researchers Erik Noftle and Richard Robins (2007) conducted a large study in