Student Summer Scholars


crayfish, visual learning, discrimination, stimuli


Medical Sciences




In nature, animals commonly experience multiple combinations of stimuli at various points in time. 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 of classical and operant conditioning. Many species of animals are known to learn via operant conditioning 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 of alarm odor, but can also learn to recognize stimuli associated with food as indicators of a feeding opportunity, and even learn social status through visual and chemical signals. Based on the results of our study, we will be able to make a definitive statement about the capabilities of crayfish to associate abstract visual shapes with food rewards. The classical conditioning trials for many days involve giving the crayfish a five-minute acclimation period in the testing tank and then releasing them for twenty minutes to explore and view the visual symbol in the presence of food each day. Eventually the food reward is removed after repeated exposure and if a learned association between the visual symbol and food reward occurs, we would expect crayfish spending a larger amount of time in the section of the tank with the reward symbol even when food is absent. Preliminary indications are that they are in fact capable of learning abstract visual symbols.