Each day, infants confront a range of normal stressful social emotional events (e.g., waiting for their caregiver to respond to their needs). But do they remember these stressful events and for how long do they remember them? The goal of this project is to examine when young infants begin to remember events and for how long they can remember them. The event chosen for this experimental study is the a disruption of normal face to face social interaction between an infant and his/her mother called the still-face (SF) in which the mother looks her infant but does not respond to her infant's attempts to play with her. A wealth of studies has shown that the SF elicits a specific reaction in infants, characterized by a decrease in positive emotions of joy and interest and an increase in negative emotions of anger and sadness engagement, an increase in looking away from the mother and an increase in coping behaviors (e.g., thumb-sucking). Infants also evidence neurophysiologic signs of stress to the SF, such as an increase in heart rate and an increase in the stress hormone cortisol. But is this still face effect something that the infants remember?
In this study the PIs will observe the emotional, heart rate and cortisol reactions of 3, 4 and 5 month old infants to two exposures to normal face-to-face play and the still-face and compare their reactions at the second exposure to infants who had no prior experience with the still-face. The second exposure will occur at 1 day, 1 week or 1 month after the first exposure. Because contextual cues aid memory we will have the mothers wear a yellow smock when they are playing and doing the still-face with their infants. Our expectation is that infants in the experimental condition will exhibit evidence for memory for the SF by looking less at the mother, and by looking away sooner, and show more negative reactions and higher heart rates and hormonal reactivity than naive infants. These reactions will be stronger the short the interval between the first and second exposure and they will be stronger the older the infant.
Much of the stress infants experience in their daily lives is social in nature, and finding out how a social event affects memory, behavior, and physiology over the first months life will fill an important gap in our understanding of how normal infant cope with and remember a stressful events. The findings from this study will provide a useful framework for clinicians and others for understanding memory and reactivity in infants exposed to trauma, or parental abuse or neglect, with implications for the early development of psychopathology, intervention, and policy.
