Attention and Self-regulation in Infancy and Toddlerhood The Early Development of Executive Functions and Effortful Control

Sammanfattning: Executive functions are higher-order cognitive functions underlying self-regulation of behavior. That is, executive functions make it possible to resolve internal conflicts and behave according to future goals rather than acting on sudden impulses or going on automatic. Very similarly, the temperamental construct of effortful control is defined as being able to inhibit a dominant response, instead acting on a subdominant response. In children, poor executive functions and low levels of effortful control have both been associated with several negative outcomes, such as lower academic achievements and externalizing behavior problems. Although these self-regulatory functions seem to play a very important role in child development, little is still known about them during the first years of life. Furthering the knowledge of early executive functions and effortful control would likely increase the chances of early detection of risks of poor development. The present thesis aimed to investigate individual differences in executive functions and effortful control in infancy and toddlerhood, as well as the early development of, and the relation between, these two functions. The thesis further aimed to investigate the relationship between the self-regulatory functions and activity level, and the possibility of predicting toddlerhood self-regulatory functions with sustained attention in infancy. In Study I, individual differences in 10-month-olds’ rudimentary executive functions were found, and these were related to temperamental activity level. In Study II, individual differences in sustained attention in infancy were found to predict toddlerhood executive functions and effortful control. Both these self-regulatory functions improved significantly from infancy to toddlerhood although the individual stability was low. Executive functions and effortful control were related in toddlerhood but not in infancy. In Study III we replicated and extended the finding of a longitudinal relation between infant sustained attention and toddlerhood executive functions. In addition, partial support for the proposition that executive functions develop in a hierarchical fashion was found, with simple inhibition being predictive of more complex forms of working memory two years later. The results from the three studies combined contribute to a better understanding of the early development of the self-regulatory functions executive functions and effortful control.