Many children will develop a number of significant behavior problems in early childhood.  Behavior problems may include shy or withdrawn behaviors, known as internalizing behaviors, and acting-out or aggressive behaviors, known as externalizing behaviors.  Although there are many contributing factors to the development of these behavior problems, research suggests that infant temperament and maternal sensitivity play important roles.  This study investigated the interaction between the early maternal sensitivity and a child’s temperament in predicting the development of internalizing, externalizing, and total behavior problems in toddlerhood.
Temperament functions as a social regulator and is a precursor to emotional and other biologically based arousal responses (e.g., “fight” or “flight” responses) when presented with social stimuli.  These biological precursors of temperament dysfunction (including impulsivity, fearfulness, and anxiety) are directly related to social functioning in early childhood.  For example, the temperament characteristics of fear, irritability, and proneness to anger may lead to aggressive or other externalizing problems, or incidences of internalizing behaviors such as social withdrawal and anxiety.

Infants may vary in what they need from their environment.  It is important that a child and his early environment establish a “fit” in order to adequately address the child’s unique needs.  In Belsky’s model of susceptibility to parenting, he suggests that infants who are temperamentally difficult may be more strongly and more negatively influenced by environmental factors such as inadequate or inappropriate parenting; these children have higher incidences of internalizing and externalizing behavior problems in toddlerhood than their temperamentally non-difficult peers.  The support and guidance a mother provides through her sensitivity play an important role not only in soothing her infant but also in providing guidance for the development of desirable self-regulatory behaviors.

The present study investigated the ability of infant temperament and maternal sensitivity to predict 24 month behavior problems in a normative sample of 88 mother-infant dyads from Baltimore, Maryland.  Mothers completed the Infant Temperament Questionnaire when their children were 4 and 12 months of age, and the Child Behavior Checklist when their infants were 24 months of age.  A 45-minute free-play interaction was used to evaluate maternal sensitivity when the infants were 4 months of age.

Externalizing behavior problems at 24 months of age was predicted by difficult infant temperament at 4 months of age and maternal sensitivity.  Maternal sensitivity also predicted internalizing and total behavior problems at 24 months of age.  Low levels of maternal sensitivity moderated the relation between 4 month difficult temperament and 24 month total behavior problems.  Results indicate that low maternal sensitivity at 4 months of age interacted with difficult infant temperament at 4 months of age to predict high incidences of total behavior problems when children are 24 months of age.

These findings suggest that a mother’s sensitivity towards her infant may buffer the negative effects of a difficult infant temperament.  A sensitive mother may help her child develop socially appropriate behaviors rather than the variety of toddler behavior problems that have frequently been associated with difficult infant temperament in the literature.

Current findings are especially intriguing given that maternal sensitivity was measured at such an early age -- when infants were four months of age.  Other studies have found similar associations when maternal sensitivity was assessed when infants were slightly older -- nine months of age.  This research demonstrates a need to evaluate maternal sensitivity early in a child’s life, before the environment has had an opportunity to affect an infant’s seemingly innate temperamental tendencies.