largely under the influence of biologically based dis-
positions and characteristics. Personality develop-
mentalists holding a strong biological orientation
argue that environmental factors do not play a signifi-
cant role in the development of individual differ-
ences, except in the case of extreme environmental
deficiencies. An example of such a deficiency is the
lack of early caregiver responsiveness described
above, which is often found with the insecure attach-
ment styles.
Biologically oriented personality theorists argue
that specific environments cannot be required for
species-typical developments such as individual dif-
ferences. Rather, environments are viewed as provid-
ing, or not providing, opportunities for biological
development to take place. All that is required for
adaptive, functional development is a range of ade-
quate environments.
As described above, early biologically based indi-
vidual differences are often characterized as differ-
ences in temperament. Considerable evidence based
on heritability research shows that individual differ-
ences in temperament have strong genetic founda-
tions. These genetic foundations lead to individual
differences in physiology, which in turn may influ-
ence environmental conditions in ways that channel
environmental experiences to fit temperamental
qualities. Put another way, biological determinants of
personality development in some ways influence and
shape the environmental conditions that influence
development.
An infant’s or child’s biological characteristics
bias his environmental experiences in a number of
ways. First, as described earlier, there is goodness-of-
fit—biologically based characteristics of an infant or
child influence his fit with the environment, which in-
directly shapes the quality of environmental experi-
ences. Second, aspects of an individual’s behavior
stemming from his biology may consistently evoke
certain types of behavior in others. For instance, a dis-
positionally timid or shy child may be ignored more
in social contexts than an extroverted child who often
initiates social exchange. Third, biologically based
dispositions may lead to certain environmental pref-
erences as an infant or child grows to increasingly se-
lect preferred environments. For example, an
individual with a particularly high activity level may
be drawn more to sports or other physical activities
while someone less active may prefer comparatively
sedentary activities. Finally, biologically based dispo-
sitions also may influence the way an individual expe-
riences environmental conditions. For example,
research has revealed very early individual differ-
ences in reactivity to novel or highly stimulating
environments arising from differences in brain func-
tioning. For highly reactive infants, novel or stimulat-
ing environments are aversive, and these infants are
likely to withdraw from such environments because
they are easily overstimulated. Given the same envi-
ronment, however, less reactive infants are likely to be
curious and want to explore.
All of these biologically based differences, which
in some ways shape an individual’s environmental ex-
periences, lead to unique environmental influences
on personality development that match the indivi-
dual’s biology. Thus, from a biological perspective, an
individual’s unique biology stands to influence the en-
vironment and therefore bias how the environment
influences personality development.
A logical next question regarding biological influ-
ences on personality development concerns the struc-
ture of personality. With personality development
having a biological component, there should be a de-
gree of universality in overall personality structure.
Research suggests that indeed there may be such a
universal structure of personality.The Developing Structure of Personality
In the field of personality psychology, there ap-
pears to be an emerging consensus that the structure
of late-adolescent and adult personality can be com-
prehensively described by five broad factors, which
are known as the ‘‘Big Five.’’ These five factors are
typically characterized as: Extroversion/Surgency,
Agreeableness, Conscientiousness, Neuroticism/
Emotional Stability, and Openness to Experience/
Intellect. Using language-based instruments cross-
culturally, the Big Five has been successfully identi-
fied in American English, German, Dutch, Portu-
guese, Hebrew, Chinese, Korean, and Japanese. Such
findings support the idea that the Big Five is a univer-
sally applicable taxonomy of late-adolescent and
adult personality.
In similar studies of infant and childhood individ-
ual difference dimensions, usually using parental or
teacher ratings of temperament, five to seven dimen-
sions are normally identified. Five of the dimensions
are particularly robust and have been labeled Activity
Level, Negative Emotionality, Task Persistence,
Adaptability/Agreeableness, and Inhibition. The two
other dimensions are less certain and have been la-
beled Rhythmicity and Threshold. Developmentally,
the process of change from these earlier infant and
childhood dimensions to the Big Five dimensions of
late adolescence and adulthood appears to involve
multiple early dimensions being subsumed under sin-
gle Big Five dimensions. In other words, during the
course of development, the organizational structure
of individual difference dimensions changes, withPERSONALITY DEVELOPMENT 303