THE TRADITIONAL PARADIGMS

Since Tolman cast the cognitive map hypothesis, many studies have been conducted, especially since the nineteen-seventies, in order to provide it with experimental support. As in Tolman’s experiments, most of the situations aimed at investigating the nature of spatial representations in rodents are multi-trial learning tasks requiring the subjects to locate and reach a generally invisible goal in a maze or an arena. Indeed, the animals must be motivated enough to complete the task. All the paradigms involve, therefore, a reinforcing event encouraging animals to implement a proficient strategy for reaching the goal either because they will find a reward there, or, alternatively, a safe place to escape from an uncomfortable medium (such as from cold water in the Morris swimming pool). Thus, these situations differ markedly from those described in the preceding chapter, which generally take place within a relatively short period of time, rely on spontaneous behavior, and (with the exception of the problem-solving tests) do not involve any explicit reinforcement. The fact that animals are repeatedly exposed to the same situation also represents a consistent difference with the formerly described paradigms. Animals subjected to a training experience may easily identify, trial after trial, the spatial relationships existing among some locations - the starting point, the choice points or the goal - which provide different views of the experimental layout, and have a particular status in the picking up of information.