Potentiation and overshadowing of shape by wall color in a kite-shaped maze using rats in a foraging task

The interaction between redundant geometric and featural cues in open field search tasks has been examined widely with results that are not always consistent. Cheng (1986) found evidence that when searching for food in rectangular environments, rats used the geometrical characteristics of the environment rather than local featural cues, suggesting that geometry had overshadowed featural cues. More recently, Graham et al. (2006) and Pearce et al. (2006) found that wall color facilitated (potentiated) learning about the shape of the environment by rats in a kite-shaped water maze. The first experiment in the present research replicated the paradigm used by Graham et al. and Pearce et al. using rats in a foraging situation, but with conditions similar, and found the same results, potentiation of shape by color. Experiments 2 and 3 revealed overshadowing instead of potentiation of shape by wall color under the same conditions except that the wall colors of the test environment were not the same as those used during training. The results are consistent with an analysis of the role of associations formed between wall color and geometry in such situations (Rhodes et al., 2009) and extend our understanding of how featural and spatial cues interact.