“…In this study, physiological data used to index RSA were sampled from mothers, limiting our focus to mothers' parasympathetic (i.e., RSA) responding to infant distress. However, the growing literature on the psychophysiology of attachment has provided evidence that individual differences in adult attachment are associated with brain activity and autonomic (both sympathetic and parasympathetic) responding to infant distress (Ablow et al., ; Groh & Roisman, ; Groh, Roisman, Haydon, et al., ; Riem, Bakermans‐Kranenburg, Van IJzendoorn, Out, & Rombouts, ; Schoenmaker et al., ; but see Leerkes et al., ). Thus, future research might examine a broader range of measures of mothers' physiological responding in relation to infant attachment (see Leerkes, Su, Calkins, Supple, & O'Brien, for a similar argument with regard to links between maternal physiological and behavioral responding).…”