Figure 1.

Mouse conditioned freezing behavior to the CS+ (odor A), the CS− (vanilla) and the two odor mixtures AB and A’B’. A) Mice froze significantly more (ANOVA, p < 0.001) to the CS+ than to any other odor, though showed a trend toward generalizing between the A’B’ mixture and A. B) Hierarchical cluster analyses of odor-evoked freezing across animals suggest that behavior toward mixture AB were clustered closely to vanilla (CS−), while the mixture A’B’ evoked behavior more similar to A (CS+). These results are consistent with an elemental perception of A’B’ and a novel configural perception of AB. See text for details.