crayfish, stimuli, conditioning, visual symbols


In nature, animals commonly experience multiple combinations of stimuli at various points intime. When two or more seemingly unrelated stimuli are detected at the same time using different sensory systems, there is the potential for an association to form between the stimuli. The animal may learn and show a response originally associated with one stimulus when it now detects the second stimulus. These stimuli are the unconditioned and conditioned stimulus ofclassical and operant conditioning. Many species of animals are known to learn via operantconditioning and a variety of responses can become associated with formerly neutral stimuli.Crayfish for example can learn new danger signals by association with the unconditioned cue ofalarm odor, but can also learn to recognize stimuli associated with food as indicators of a feedingopportunity, and even learn social status through visual and chemical signals. Based on theresults of our study, we will be able to make a definitive statement about the capabilities ofcrayfish to associate abstract visual shapes with food rewards. The classical conditioning trialsfor many days involve giving the crayfish a five-minute acclimation period in the testing tankand then releasing them for twenty minutes to explore and view the visual symbol in thepresence of food each day. Eventually the food reward is removed after repeated exposure and ifa learned association between the visual symbol and food reward occurs, we would expectcrayfish spending a larger amount of time in the section of the tank with the reward symbol evenwhen food is absent. Preliminary indications are that they are in fact capable of learning abstractvisual symbols.