BIOLOGICAL STRESS RESPONSE FUNCTIONING AND BEHAVIORAL FEAR REGULATION IN AT-RISK INFANTS

Emotion regulation in infants is an early indicator of mental health, and dysregulation has been linked to later behavioral and psychiatric problems. The relationship between infant hypothalamic pituitary adrenal axis functioning and infant emotion regulation has been previously studied, but results have been inconsistent; additionally, previous work has focused on primarily middle- to upper- socioeconomic, Caucasian populations. We examined if infant diurnal cortisol is associated with behavioral regulation of fear in a low-income, racially and ethnically diverse sample. Infants from this sample may be at greater risk for dysregulated stress response system functioning and deficits in emotion regulation due to environmental stressors associated with poverty. Understanding these processes in this sample is critical for intervention efforts to support healthy developmental trajectories among infants with early adversity. The sample for data analysis consisted of 39 mother-infant dyads at 6 months postpartum. Data from 120 dyads will be available for the presentation. Approximately half of the infants were female (51%), and infants were racially and ethnically diverse (49% Hispanic, 27% Black, 22% White). A majority of families were low-SES (66% < $30,000 per year, 61% unemployed). To examine infant HPA axis functioning, mothers collected saliva samples in the home at 6 months postpartum four times per day for three days to measure infant diurnal cortisol levels. Infants also engaged in an emotionally arousing task during a 6-month videotaped laboratory assessment where they observed a remote control truck moving and making loud sounds for 3 minutes, then remaining still and within arm reach for one minute. Videotapes were continuously coded on a second-by-second basis using Mangold INTERACT for discrete infant emotion regulation behaviors. Simple correlations were used to examine if diurnal cortisol levels at each of the four collection times, in addition to change in cortisol across the day, were associated with infant behavior. Higher cortisol levels at 12 pm, 2 pm, and bedtime were significantly associated with more time crying (r = .38, .35, and .33 respectively, p < .05) and looking at the mother (r = .36, .35, and .37 respectively, p < .05). Lower 12 pm and bedtime cortisol levels were significantly associated with more time engaging in stimulation/play behaviors (r = -.38 and -.39 respectively, p <.05). Change in cortisol across the day was significantly associated with more time looking away from the stimulus (r = 0.37, p <.05). Our results demonstrate that diurnal cortisol levels are associated with specific types of infant fear regulation. Infants with higher afternoon cortisol may be more easily distressed, and may utilize the mother more to regulate their distress. Infants with lower afternoon cortisol may exhibit more independent emotion regulation strategies. Infants with greater change in cortisol may also exhibit more independent regulation strategies and less dyadic strategies.