Sigma Xi Student Research Showcase

  The purpose of this experiment was to study the adverse cognitive effects of microplastics on the freshwater snail, Pomacea diffusa. Hypothesis: exposure to microplastics will impair their learning in an operant conditioning paradigm. Procedures: Twenty snails were randomly assigned to two groups: one group exposed to 100,000 particles/ml of  micro and nanoplastics added to their environment and a control group having no microplastics added. Both groups underwent an operant conditioning using a conditioned taste aversion protocol. The feeding response (number of bites in one minute) following the application 1 ml of 100 mM sucrose solution was measured for each snail 24 hours before the conditioning and again 10 minutes after conditioning. Results: The snails exposed to microplastics averaged a decrease of only 4.4 bites per minute following conditioning while the control snails averaged a decrease of 13.0 bites/minute. Conclusions: Microplastics interfere with operant conditioning in Pomacea suggesting they may impair learning. Applications: The possibility that microplastics may impair learning and cognition has significant implications for their potential toxicity in humans who have seen a rise in autism and ADHD. These results should be investigated further and add to the urgency to reduce plastics use.