Mental planning and the Tower of London task

Abstract

The Tower of London (TOL) task has been used extensively as a test of planning ability in neuropsychological patients and normal populations. Participants are asked to preplan mentally a sequence of moves to match a start set of discs to a goal, and then to execute the moves one by one. The mental preplanning stage has been identified as critical to efficient performance. The current experiments examined whether manipulations of mental preplanning influence performance on the TOL. In Experiment 1, the effect of different planning instructions was examined. Those told to make full mental plans spent considerably longer in planning than participants given no specific planning instructions, yet there was no effect of instruction condition on the efficiency of executing plans. Experiment 2 investigated whether people were able to plan mentally, by looking at their ability to identify intermediate states of an optimum mental plan. Results indicated that most individuals could make accurate preplans up to two subgoals ahead, but not three. However, making an efficient preplan did not result in better subsequent execution of moves to solve the TOL trial. It is concluded that people can make effective mental plans for a limited number of moves. However, on the TOL task, mental preplanning does not offer benefits in terms of quicker performance, or more accurate solution. The nature of planning in the TOL task is therefore questioned.

The roles of private speech and inner speech in planning during middle childhood: Evidence from a dual task paradigm

“…Articulatory suppression was not detrimental to performance accuracy (defined in terms of the number of excess moves) for problems of any level of difficulty. The effect of articulatory suppression was only to speed up performance, although its effect in reducing planning times (time to first move) mainly occurred for the most Running head: ROLES OF PRIVATE AND INNER SPEECH IN PLANNING difficult problems, which were too complex to be planned in full even with no secondary task (Phillips, Wynn, McPherson, & Gilhooly, 2001). …”

Convex hull or crossing avoidance? Solution heuristics in the traveling salesperson problem

“…Research in other areas of problem solving has suggested that this capacity may be quite limited (MacGregor, Ormerod, & Chronicle, 2001;Phillips, Wynn, McPherson, & Gilhooly, 2001). In the case of E-TSPs, it has been reported that normal subjects plan a small section of the route before the first move and then program their moves during execution, exhibiting a constant degree of planning in the process (Basso et al, 2001).…”

The impact of working memory load on task execution and online plan adjustment during multitasking in a virtual environment

“…In contrast, if on-line plan adjustment during the test is sufficient for good performance, participants in the poor plan group should be able to overcome their disadvantage. For example, Phillips, Wynn, McPherson and Gilhooly (2001) showed that pre-planning of a complex single task (Tower of London) did not lead to better performance; online planning was an equally effective approach to the task and was also preferred by the majority of participants. In contrast, Logie et al (2011) showed that, although people who started with a good (self-generated) plan performed better than people who started with a poor plan, participants who used their original plan (good or bad) tended to perform better than participants who changed their plans on-line.…”