Tower of London
Plan your moves to match the goal
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What is the Tower of London?
The Tower of London is a classic planning puzzle used in neuropsychology. Tim Shallice created it in 1982 to study planning in people with frontal lobe damage. In the standard version, three coloured balls sit on three pegs of different heights, and you must rearrange them to match a goal picture in as few moves as possible. Researchers use it because a good score depends on thinking several moves ahead before touching anything.
Tower of London on Neuroptimize keeps the familiar layout of three pegs holding up to three, two and one ball. Each puzzle shows a goal picture and a par, the minimum number of moves, and you tap pegs to move balls one at a time. At the highest levels a fourth ball and taller pegs appear, so longer plans are needed to reach the goal efficiently.
How to play the Tower of London
- The small picture at the top shows the goal arrangement. Your job is to make the large board below match it exactly.
- Tap a peg to lift its top ball, then tap another peg to drop it there. Tap the same peg again to put the ball back down. Only the top ball on a peg can move.
- Each peg has a limited height. If you try to drop a ball onto a full peg, the peg shakes and the move is not counted.
- The pills show the par (the minimum number of moves) and your move count. A puzzle counts as solved if you match the goal within par plus 1 move, and matching it exactly at par earns a bonus.
- Reset returns the balls to the start, but moves already made still count. If you go over par plus 1, a Skip button appears, and skipping counts as a miss.
- A session has 6 puzzles with no time limit. Par rises from 2 moves at level 1 to 7 by level 24. From level 25 a fourth ball is added, the pegs hold four, three and two balls, and par climbs to 9.
Strategies and tips
Plan every move first
Before tapping, trace the whole sequence in your head and count it against par. A perfect score needs the full plan, because one careless move usually costs two moves to undo.
Fill the goal from the bottom
Balls at the bottom of a goal peg must be placed first. Look at which ball goes in the lowest slot of each peg and plan to get it there before stacking anything on top.
Work backwards from the goal
Ask which ball must be placed last, then which ball must be moved out of the way before that. Reasoning backwards often reveals the order of moves more quickly than trial and error.
Use the short peg as a parking spot
The shortest peg is ideal for holding a ball temporarily while you dig out the one beneath. Just make sure the parked ball will not block the next step of your plan.
Avoid moving a ball twice
Solutions at par rarely move the same ball back and forth. If your plan lifts a ball and later returns it to where it started, look for a route that leaves it alone.
The science behind the Tower of London
The Tower of London test was devised by Tim Shallice in 1982 to assess planning in patients with frontal lobe damage. Participants rearrange coloured beads on pegs to match a goal arrangement in the fewest moves, which requires working out a sequence of moves before starting.
Frequently asked questions
What does the Tower of London test measure?
It is used in research and clinical assessment to measure planning, specifically the ability to work out a sequence of moves before acting. It was designed by Tim Shallice in 1982 to study planning after frontal lobe damage.
What is the difference between the Tower of London and the Tower of Hanoi?
The Tower of Hanoi uses discs of different sizes and forbids placing a larger disc on a smaller one. The Tower of London uses same-sized coloured balls on pegs of different heights, and each puzzle has its own goal arrangement to match.
How do you solve Tower of London problems in the fewest moves?
Plan the whole sequence before moving, place the balls at the bottom of each goal peg first, and use the shortest peg as a temporary holding spot. Working backwards from the goal helps show which ball needs to move when.
Is Tower of London free on Neuroptimize?
Yes, it is a free game. It unlocks once your Neuroptimize account reaches level 13.