Pattern Cue and Visual Cue Competition in a Foraging Task by Rats

In 4 experiments, rats searched for food located on top of 4 of 16 towers which were arranged in a 4 x 4 matrix. The location of the baited towers was cued by visual landmark cues (the baited towers were striped, the others white) and by pattern cues (the baited towers were located in a 2 x 2 pattern within the larger 4 x 4 matrix) or simply by pattern cues without visual landmark cues. In 3 of the experiments, visual cues, after being paired with pattern cues, were removed altogether (Experiment 1), put into competition with pattern cues (Experiment 2), or made noninformative (Experiment 3). In Experiment 4, it was the pattern cues that were made noninformative. Collectively, the data suggest strongly that whereas the pattern is learned, even when presumably more salient visual cues are present, the connection between pattern and food location is much weaker than that between visual cue and food location. These data are more easily explained by a model of learning that includes dedicated modules than by a single-system associative model.