Working memory capacity predicts focus back effort under different task demands.

According to the cognitive flexibility view, individuals with higher cognitive control ability are more flexible in experiencing on task or mind wandering during tasks with different loads. On the other hand, the resource-control theory posits that executive control is essential for allocating attentional resources between mind wandering and tasks. Focus back effort may reflect the adjustment of executive control in the resource-control theory. Here, 121 participants completed two span tasks, as well as high- and low-load tasks, while mind wandering and focus back effort were measured. Our findings indicated that mind wandering was influenced by working memory capacity (WMC) and focus back effort. Additionally, participants demonstrated a higher focus back effort during the higher load task. This effect was particularly pronounced in individuals with lower WMC, which was treated as a continuous variable. These findings integrate the cognitive flexibility view and resource-control theory to describe how individuals modulate mind wandering.