Individual Differences in the Effectiveness of Maternal Soothing Behaviors

On Infant Stress Response

 

A variety of research has investigated individual differences in infants’ reactivity to stress, but few have also considered how mothers differ in their soothing behaviors in response to infant distress.  The present study investigates individual differences in the effectiveness of eight maternal regulatory behaviors on reducing the intensity and duration of 2- and 6-month-old’s stress response to an inoculation.  Additionally, we examine the stability of these behaviors as well as that of infants’ stress response.

As part of a longitudinal study, 146 infants and their mothers were videotaped following an inoculation at 2 and 6 months.  The infants’ and mothers’ behaviors were coded off-line from the moment the infant received the shot, until he or she stopped crying.  For the purposes of our analyses, we focused on a period of 4 minutes after the start of the inoculation.  Behaviors were coded during each 5-second interval, for a total of 48 intervals.  Infant reactivity was coded according to a 4-point scale, representing an increasing intensity of crying: 0=none, 1=fuss, 2=low cry, 3=high cry.  During the same 5-second intervals, the presence/absence of any of the following maternal behaviors was coded: Affection, Touching, Holding or Rocking, Vocalization, Caretaking, Distraction, Face to Face interaction, and Feeding or use of a Pacifier. 

Consistent with prior studies (e.g., Worobey & Lewis, 1989), we found significant stability across age in the intensity of infant cry response (r = .19, p<.04), but no stability in the duration of crying across age (r = .06, p<.5).  With respect to maternal soothing behaviors, the following behaviors showed significant stability from 2 to 6 months: Affection (r = .323, p<.001), Touching (r = .307, p<.001), Vocalizing (r = .353, p<.001), Caretaking (r = .204, p<.03), and Feeding/Pacifying (r = .180, p<.04).  To test the hypothesis that maternal soothing behaviors may have influenced the lack of stability in cry duration, a Yule’s Q score was calculated for each dyad, representing the effectiveness of each of the eight behaviors.  The mean of these scores across all eight behaviors was used as an index of the overall effectiveness of each mother at reducing her infant’s stress response.  The results suggest that the effectiveness of these maternal behaviors on infant stress response varies.  Correlation analyses revealed that overall effectiveness at 2 months was significantly negatively associated with cry duration at 2 months (r = -.18, p<.03), and significantly negatively associated with both cry duration (r = -.19, p<.03) and cry intensity (r = -.20, p<.02) at 6 months.  These findings may support a model of external to internal emotion regulation (Thompson, 1994).  Follow-up analyses will examine the predictive nature of each specific maternal soothing behavior on both concurrent and subsequent infant reactivity.