Salivary α-amylase and intended harsh caregiving in response to infant crying: evidence for physiological hyperreactivity.

This is the first study on adults' physiological reactivity to infant cry sounds and the association with intended harsh parenting using salivary α-amylase (sAA) as a novel and noninvasive marker of autonomic nervous system activity. The sample consisted of 184 adult twin pairs. In an experimental design, cry sounds were presented and adults' perception and their intended caregiving responses were measured. Saliva samples were collected after each cry sound. For the majority of the sample, a decrease in sAA across the cry paradigm was observed. However, adults who indicated that they would respond in a harsh way to the crying infant were significantly less likely to show a decrease in sAA. Consistent with previous studies on physiological hyperreactivity in abusive parents, these findings suggest that failure to habituate to repeated infant crying may be one of the mediating mechanisms through which excessive, inconsolable, and high-pitched infant crying triggers less optimal caregiving.