Early childhood is characterized by rapid increases in both motor skills and executive function skills. Rather than simply codeveloping, the development of motor and executive function skills may be linked causally. In this article, we introduce corticomuscular coherence as a paradigm for psychologists interested in testing mechanistic questions about the potentially causal association between motor and executive function skill development in early childhood. We also consider the broader implications of this work for informing typical and atypical development.