ABSTRACT
In the summer of 2001, one of us (PB) was having a discussion with Professors Tim Shallice and Donald T. Stuss. The topic of discussion was the processing demands of everyday life situations, and the example we were discussing was making grocery purchases in a supermarket. Both professors pointed out that they habitually checked and compared the prices of different brands before they bought them. In fact they would occasionally go as far as checking the weight or quantity of the packet, and making a brief assessment of its relative value compared with some other size or volume. Often they would plan where to go on the basis of their knowledge of relative prices. Moreover, when in a particular place for some other reason, they might consider making local purchases in advance of when the food would be consumed, given that it made financial and practical sense. Clearly the formation and execution of strategies to minimize expense and effort that they were describing constitute “planning” at some level: They had a goal state which they wished to achieve (full stomachs) and many constraints they had to negotiate (spending as little money as possible; buying food that they could cook which would meet the approval of their own and others’ tastes; the availability both present and in the future of various ingredients; storage of the food and its perishability in relation to their weekly schedule and so forth). However, PB was unsettled by this discussion since he never indulged in this behaviour: Perhaps this meant that he had no planning ability.
