Practice schedules and subgoal instantiation in cascaded problem solving

Fluent problem solving depends on efficient instantiation of subgoals for executing component skills. In 3 experiments, the authors examined how component-skill practice schedules and problem-solving demands interact to affect fluency in mental calculation. Participants practiced Boolean rules in blocked or random practice schedules and then solved problems that varied in the need to switch rules and in preview of upcoming operators. In Experiment 1, participants more quickly solved problems requiring repeated use of a single rule than problems using multiple rules, but practice schedules had no effect. In Experiment 2, random practice produced a transfer benefit for multiple-rule problems that allowed operator preview. Experiment 3 verified the importance of preview. These results suggest that when participants can rapidly switch rules, they achieve fluency by overlapping steps in a manner analogous to perceptual-motor skills.