A LONGITUDINAL STUDY OF INFANT CORTISOL RESPONSE DURING LEARNING EVENTS

• Published in: Monographs of the Society for Research in Child Development 2015-01, Vol.80 (4), p.i-143
• Main Authors: Thompson, Laura A., Morgan, Gin, Jurado, Kellie A., Gunnar, Megan R., Bauer, Patricia J.
• Format: Article
• Language: English
• ISSN: 0037-976X; 1540-5834

Cortisol, a hormone associated with the stress response, has been shown to affect adult performance on learning and memory tasks, yet whether cortisol helps or hinders performance depends on the direction of cortisol change during the task, the amount of change, and the type of task. Past studies of infants are few and conflicting regarding whether an increasing or decreasing cortisol reactivity pattern facilitates cognitive performance. Similarly, few studies have assessed whether an association exists between maternal sensitivity and learning in infancy. Studies that have examined the effects of cortisol response or maternal sensitivity on cognitive performance have tended to focus on specific ages during infancy, with no direct investigation of stability or developmental progression of these measures across the first year of life. The present study assessed relations between maternal sensitivity, infants' cortisol response to maternal separation and a novel cognitive task, and cognitive performance at 3, 6, 8, 10, and 12 months. At each phase, infants completed different cognitive tasks, maternal and infant cortisol was measured before and after the task, and mother–infant behavior was assessed to determine maternal sensitivity. When performance on the cognitive tasks varied as a function of cortisol response or maternal sensitivity, better performance was associated with a decreasing pattern of cortisol response (lower cortisol after the task than before) and higher levels of maternal sensitivity. The relation between cortisol response and infant cognitive performance was not, however, mediated by maternal sensitivity. Longitudinal analyses revealed no intra-individual stability in infants' cortisol response patterns over the first year; however, at the group level, the decreasing cortisol response pattern became more prevalent across this age range, especially in girls. Additionally, beginning at 6 months, maternal sensitivity was stable across phases. Results are discussed in terms of their implications for the development of regulation abilities during infancy. In this monograph titled "A Longitudinal Study of Infant Cortisol Response During Learning Events," Laura A. Thompson, Gin Morgan, and Kellie A. Jurado describe the results of an important study of the associations between maternal sensitivity and adrenocortical activity as they influence infant learning over the first year of life. Although the researchers argue that the work can be understo