Changes in working memory influence the transition from reactive to proactive cognitive control during childhood.

Cognitive control develops rapidly over the first decade of life, with one of the dominant changes being a transition from reliance on 'as-needed' control (reactive control) to a more planful, sustained form of control (proactive control). Although the emergence of proactive control is important for mature behavior, we know little about how this transition takes place, the neural correlates of this transition, and whether development of executive functions influences the ability to adopt a proactive control strategy. This study addresses these questions, focusing on the transition from reactive to proactive control in a cross-sectional sample of 79 children-forty-one 5-year-olds and thirty-eight 9-year-olds. Children completed an adapted version of the AX-Continuous Performance Task while electroencephalography was recorded and a standardized executive function battery was administered. Results revealed 5-year-olds predominantly employed reactive strategies, whereas 9-year-olds used proactive strategies. Use of proactive control was predicted by working memory ability, above and beyond other executive functions. Moreover, when enacting proactive control, greater increases in neural activity underlying working memory updating were observed; links between working memory ability and proactive control strategy use were mediated by such neural activity. These results provide convergent evidence that the transition from reactive to proactive control may be dependent on age-related changes in neurocognitive indices of working memory and that working memory may influence adopting a proactive control strategy.