A Longitudinal Study of Infant Cortisol Response During Learning Events

A Longitudinal Study of Infant Cortisol Response During Learning Events by Laura A. Thompson, Gin Morgan, and Kelly A. Jurado explores the intricate dynamics of cortisol, a hormone linked to the stress response, and its impact on learning and memory tasks in adults. The interplay of cortisol's direction of change, the magnitude of this change, and the type of task it affects is crucial in determining whether performance is helped or hindered.

Past research on infants has produced inconsistent findings on whether an increasing or decreasing cortisol reactivity pattern supports cognitive performance. The exploration of the association between maternal sensitivity and learning in infancy has been similarly limited.

This study investigates the relationships between maternal sensitivity, infants' cortisol response to maternal separation and novel cognitive tasks, and cognitive performance at 3, 6, 8, 10, and 12 months. Throughout each phase, infants engaged in various cognitive tasks, with both maternal and infant cortisol levels measured pre- and post-task. Additionally, mother-infant behaviour assessments were conducted to evaluate maternal sensitivity.

The findings indicated that better cognitive performance correlated with a decreasing pattern of cortisol response (lower cortisol after the task than before) and higher maternal sensitivity. However, maternal sensitivity did not mediate the relationship between cortisol response and infant cognitive performance.

Longitudinal analyses showed no intra-individual stability in infants' cortisol response patterns over the first year. Nevertheless, at a group level, a decreasing cortisol response pattern became more prevalent across this age range, particularly in girls. From 6 months onwards, maternal sensitivity remained stable across phases.

The results hold significant implications for understanding the development of regulatory abilities during infancy and underscore the nuanced interplay between biological and environmental factors.