Parasympathetic and sympathetic responses to the strange situation in infants and mothers from avoidant and securely attached dyads.

Vagal reactivity and salivary alpha-amylase (sAA) were assessed in infants (M age = 13.55 months) and their mothers during the Strange Situation Paradigm (SSP) to investigate differences in physiological responses in a sample of insecure-avoidant and securely-attached dyads (N = 132). Infants classified as insecure-avoidant had significantly higher vagal withdrawal during the SSP and higher sAA overall, suggesting that the avoidant attachment pattern is associated with a greater allostatic load. During separation episodes of the SSP, all mothers showed significant vagal withdrawal, suggesting greater attempts at regulation. During the last reunion, typically the most stressful episode for infants, mothers of secure infants showed greater vagal withdrawal than mothers of insecure-avoidant infants, suggesting greater attempts by these mothers at interactive repair. Results for mothers and infants supported the allostatic load theory.