An analysis of associative learning in a terrestrial mollusc - I. Higher-order conditioning, blocking and a transient US pre-exposure effect

We have recently demonstrated that associative learning can play an important role in the regulation of food selection behavior of Limax maximus, a terrestrial mollusc. The tendency of Limax to approach a normally attractive odor generated by a food source such as carrot or potato can be markedly reduced if exposure to that odor is paired with exposure to a bitter taste (quinidine sulfate). We now report that variables known to influence associative learning by vertebrates (the operations of a second-order conditioning procedure, blocking and US-pre-exposure) similarly influence associative learning by Limax.