Left, right, left, right: 24-36-months-olds' planning and execution of simple alternating actions.

This study investigated toddlers' ability to control simple alternating pattern actions, and how this relates to motor competence and executive functions. 70 toddlers between 24 and 36 months of age were instructed to sort coins in an alternating pattern into two boxes; left, right, left, right etc. Executive functions and memory competence performance were assessed in additional small games. The results showed that the ability to plan and execute actions according to a simple extended alternating pattern improved over toddlerhood. Furthermore, working memory and motor competence scores were both independent predictors of the ability to plan and execute simple alternating actions. These findings underscore the fact that between 24 and 36 months of age is a period in which the ability to string together multiple actions in a sequence to achieve a distal goal is still developing.