Two experiments investigated 1st-, 3rd-, and 5th-grade children's and adults' judgments related to the controllability of cognitive activities, including object recognition, inferential reasoning, counting, and pretending. In Experiment 1, fifth-grade children and adults rated transitive inference and interpretation of ambiguous pictures as more effortful than object recognition or deduction by elimination, and first-grade children rated transitive inference as more effortful than deduction by elimination. In Experiment 2, third- and fifth-grade children rated it more difficult to arrive at alternative outcomes for object recognition than for pretending, and adults distinguished object recognition and deduction from pretending and interpreting ambiguous pictures. From first-grade to adulthood there were increases in the number of distinctions made among cognitive activities in terms of level of controllability.