Personality Development

From a more biological perspective, personality development is thought to be primarily governed by the biological maturation of the individual. Even environmental influences on development are viewed as largely under the influence of biologically based dispositions and characteristics. Personality developmentalists holding a strong biological orientation argue that environmental factors do not play a significant role in the development of individual differences, 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 attachment styles.

Biologically oriented personality theorists argue that specific environments cannot be required for species-typical developments such as individual differences. Rather, environments are viewed as providing, or not providing, opportunities for biological development to take place. All that is required for adaptive, functional development is a range of adequate environments.

As described above, early biologically based individual differences are often characterized as differences in temperament. Considerable evidence based on heritability research shows that individual differences in temperament have strong genetic foundations. These genetic foundations lead to individual differences in physiology, which in turn may influence 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-offit—biologically based characteristics of an infant or child influence his fit with the environment, which indirectly shapes the quality of environmental experiences. Second, aspects of an individual's behavior stemming from his biology may consistently evoke certain types of behavior in others. For instance, a dispositionally 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 preferences as an infant or child grows to increasingly select 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 dispositions also may influence the way an individual experiences environmental conditions. For example, research has revealed very early individual differences in reactivity to novel or highly stimulating environments arising from differences in brain functioning. For highly reactive infants, novel or stimulating environments are aversive, and these infants are likely to withdraw from such environments because they are easily overstimulated. Given the same environment, 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 experiences, lead to unique environmental influences on personality development that match the individual's biology. Thus, from a biological perspective, an individual's unique biology stands to influence the environment and therefore bias how the environment influences personality development.

A logical next question regarding biological influences on personality development concerns the structure of personality. With personality development having a biological component, there should be a degree of universality in overall personality structure. Research suggests that indeed there may be such a universal structure of personality.