How the tower game works
Pymetrics’ 2017 US patent names the Tower of London as the task behind its Towers game. In the patent’s version you see two sets of three pegs. The target set has five coloured discs on one peg; the working set has the same five discs spread across its three pegs. Your job is to move discs in the working set until it matches the target. People who finish within the time allowed and in the minimum number of moves are assessed as having high planning ability.
Pymetrics does not publish a newer description, a round count or a time limit for the live game, so treat the patent as the best public account rather than an exact specification.
What it measures
The patent describes the Tower of London as a test of executive function and planning. Researchers record the number of moves and the initial thinking time, the gap between the puzzle appearing and your first move. A longer initial thinking time tends to go with fewer moves, which is why it is read as planning.
Difficulty rises with the minimum number of moves a puzzle needs. The patent notes that low, medium and high performers solve puzzles up to correspondingly low, medium and high minimum-move levels, but not above. Pymetrics reported reliability for time on the task of .77 split-half and .69 test-retest.
How to approach it
Plan before you touch anything. The research measures how long you think before the first move as well as how many moves you make, and the patent rewards solutions in the minimum number of moves. Work out where the bottom disc of the target peg has to come from, because it must be in place before anything can sit on it.
How our practice version works
Our Tower practice is a Tower of Hanoi, not a Tower of London. You move a stack of numbered discs from the left peg to the right peg without ever putting a larger disc on a smaller one, over 8 rounds of 3, 4 and 5 discs with 90 seconds each. Both are classic planning puzzles, and ours records your moves against the minimum, but the goal differs from the patent’s task of matching a target arrangement of coloured discs. Expect the real puzzle to look different, and read its instructions carefully.