Personality Development

Many personality theorists and researchers emphasize the importance to early personality development of the quality of attachment between infant and primary caregiver. Attachment is considered the enduring emotional tie that an infant forms with his caregiver, which helps to ensure a relationship style between caregiver and infant that fosters infant survival. Several models characterize the developmental progression of attachment formation. These models emphasize the universal, biologically based process of attachment as it unfolds across infancy and childhood.

Significant individual differences are not thought to occur in the actual process of attachment formation itself, but individual differences do occur in the quality or style of attachment. See Table 1 for a listing of the commonly agreed upon infant and childhood attachment patterns and their characteristic behaviors. These patterns of behavior have been identified through a laboratory procedure called the Strange Situation, which was developed by Mary Ainsworth and her colleagues. The Strange Situation is a standardized procedure that places the infant or young child in increasingly stressful separation-reunion situations with the caregiver.

Many contributing factors lead to differences in attachment style, but the developmental factor typically viewed as most important to attachment outcomes is caregiver responsiveness to infant needs. For example, a caregiver facilitates a secure attachment by consistently meeting the infant's needs. Infant needs may be satisfied by behaviors such as responding to crying, feeding when hungry, physical contact, and comforting during times of stress. If the infant's needs are met consistently, a secure attachment is most likely formed through the infant learning to expect the caregiver's responsiveness and dependability.

If an infant's needs are not met consistently, then one of the insecure attachment patterns is more likely to develop. These insecure attachment patterns may lead to later peer and romantic relational problems in adolescence and early adulthood. Table 2 shows some adolescent and early-adulthood characteristics that researchers have found to be related to different earlier attachment patterns. Table 2 includes only the first three attachment styles listed in Table 1. Since the 1990s, researchers have identified the fourth attachment style, insecure-disorganized-disoriented, and have not studied the outcomes that might be associated with it.

Some research has revealed a relation between infant temperament and attachment style. Infants classified as temperamentally difficult—characterized by irritability, adverse reactions to changes in routine, and unpredictable endogenous rhythms, like wake/sleep cycles, are more likely to form one of the insecure attachment styles. This relation between temperament and attachment suggests that temperament can influence the process of attachment. For instance, a temperamentally difficult infant is in many ways more difficult and less satisfying to care for than a more easygoing infant. The increased burden of caring for a difficult infant makes it less likely that the infant's needs will be met as consistently as those of the more temperamentally easygoing infant. These relationship differences between caregivers and temperamentally different infants stand to shape different attachment patterns.

Becoming increasingly popular in assessing the relative contributing factors in early personality development is the concept of goodness-of-fit between the developing infant or child and his or her environment. In the example above of the temperamentally difficult infant being more likely to form an insecure attachment, if the particular caregiver is not negatively affected by the difficult behaviors of the infant, then an insecure attachment is less likely to occur because of the good fit between the caregiver and infant. The goodness-of-fit between an infant or child and her environment is as important in determining developmental outcomes as different developmental factors (e.g., parental responsiveness, temperament) considered separately.