• total testing session: about 2 hours
• Before the main test, the participants were asked to complete 5 practice problems of increasing difficulty (one move, two moves, etc.) to ensure participants understood the rules.

Main task:

• 10 blocks of 9 TOL problems each (90 TOL problems total) were administered, where the order of the blocks were randomly generated for each participant.
• Order of difficulty: 3-move problem, then 5-move problem, then 4-move problem, etc.
• Subjects were instructed to plan their moves before moving any circles.
• Subjects had no time limit, but were limited to a maximum amount of moves (2 times the min. number of moves plus 4).