Spatial working memory is necessary for actions to guide thought.

Directed actions can play a causal role in cognition, shaping thought processes. What drives this cross-talk between action and thought? I investigated the hypothesis that representations in spatial working memory mediate interactions between directed actions and problem solving. Participants attempted to solve an insight problem while occasionally either moving their eyes in a pattern embodying the problem's solution or maintaining fixation. They simultaneously held either a spatial or verbal stimulus in working memory. Participants who moved their eyes in a pattern that embodied the solution were more likely to solve the problem, but only while also performing a verbal working memory task. Embodied guidance of insight was eliminated when participants were instead engaged in a spatial working memory task while moving their eyes, implying that loading spatial working memory prevented movement representations from influencing problem solving. These results point to spatial working memory as a mechanism driving embodied guidance of insight, suggesting that actions do not automatically influence problem solving. Instead, cross-talk between action and higher order cognition requires representations in spatial working memory.