In this task, an individual views a series of three balls on a peg in a start position that must be moved to a pre-specified goal configuration on three other pegs, one of which can support one ball, one of which can support two balls, and one of which can support three balls. The subject is instructed to replicate the goal configuration using the smallest number of moves. The number of moves and time required to reach the goal position is the dependent measure. The task measures not only how well an individual can organize sequential behavior to reach a goal but also whether one can inhibit acting before a plan is fully formed.
Berg, W. K. & Byrd, D. L. (2002) The Tower of London Spatial Problem Solving Task: Enhancing Clinical and Research Implementation. Journal of Experimental and Clinical Neuropsychology, 25(5), 586-604.