Working memory is a central cognitive system that plays a key role in development, with working memory capacity and speed of processing increasing as children move from infancy through adolescence. Here, I focus on two questions: What neural processes underlie working memory, and how do these processes change over development? Answers to these questions lie in computer simulations of neural-network models that shed light on how development happens. These models open up new avenues for optimizing clinical interventions aimed at boosting the working memory abilities of at-risk infants.