Releaser-induced recognition learning by gastropod molluscs.

The releaser-induced recognition learning model (Suboski, 1990) is briefly introduced and examined in the context of a review of the extensive literature on learning by gastropod molluscs. Substantial involvement of learning processes were found to occur in the acquisition of food and environmental hazard recognition. These findings are consistent with a learning model in which releasing stimuli activate a stimulus-substitution mechanism that induces recognition of otherwise biologically inert stimuli. According to this model, simple recognition learning by molluscs basically consists of the stimulus redirection of innately-organized released responses. A releasing stimulus activates transfer of control over release of responses from the releasing stimulus to an initially-neutral stimulus, typically a temporal predictor of the releasing stimulus. The model offers a simple, parsimonious, and comprehensive account of molluscan learning that integrates Pavlovian and at least simple instrumental conditioning as well as providing a potential explanatory mechanism if intriguing indicators of social communication of food recognition by gastropods were to be substantiated.