[Possibility of solving complex problems by recursive thinking].

This study examined the ability in recursive thinking to solve problems. To think recursively is one of the most effective ways to break up large and complex problems into smaller ones. This study prepared two problems with the same tail recursion: The "Guess-the-Number game" and the "Hat puzzle (Wise men puzzle)." Because participants (N = 35) were not familiar with recursive thinking, they learned how to think recursively in the Guess-the-Number game. Then, we tested whether they could solve the Hat puzzle recursively. The results show that two-thirds of the participants could solve the problem recursively, even if the size of the problem increased. Furthermore, their solution times had differed between correct and incorrect answers. This suggests that the difference reflected a "saving" of effort for problem solving.