Elemental and configural learning and the perception of odorant mixtures by the spiny lobster Panulirus argus

The present study used a conditioning assay to investigate if the type of learning task that spiny lobsters (Panulirus argus) were required to perform influenced the way that they perceived odorant mixtures. Mixtures were composed of 2 food-related compounds (adenosine-5'-monophosphate, betaine, or L-glutamate) at concentrations that produced the same duration of searching behavior in unconditioned animals. Aversive conditioning of search behavior coupled with generalization testing was used to evaluate perceptual similarity between related mixtures. When animals were conditioned to stop searching to a binary mixture AX, they did not generalize significantly from this mixture to either of its components (A or X), or to a binary mixture containing one novel component (AY). However, when lobsters were conditioned to avoid AX but to continue responding to AY, they generalized between AX and X and between AY and Y. The results support the hypothesis that altering the salience of a mixture's components by giving them different reinforcement contingencies changed the way that the mixtures were perceived. As a result of such conditioning, animals perceived the mixture's components as separate elements, rather than as a configuration, and, as a consequence, animals generalized between binary mixtures and their most salient or predictive components.