Primacy and recency in snails (Cornu aspersum)

Area of Science:

• Animal Cognition
• Behavioral Neuroscience
• Invertebrate Learning

Background:

• Pavlovian conditioning is a key tool for studying associative learning and memory.
• Primacy and recency effects, where initial and final items in a series are better recalled, are known memory phenomena.

Purpose of the Study:

• To investigate the presence of primacy and recency effects, known as the serial position effect, in terrestrial snails (Cornu aspersum).
• To explore associative learning and memory capabilities in invertebrates using a novel conditioning procedure.

Main Methods:

• Utilized a tentacle lowering procedure for appetitive conditioning in snails.
• Paired five distinct odorous conditioned stimuli (CS) with food reinforcement.
• Assessed conditioned responses (CR) to CSs presented alone in a conditioning test.

Main Results:

• Experiment 1 showed higher CRs for the first and last odors in a series, indicating a serial position effect.
• Experiment 2 confirmed that a 20-minute trial is sufficient for appetitive conditioning in snails.
• Experiments 3 and 4 replicated these findings, controlling for odor order and minimizing inter-trial intervals.

Conclusions:

• Provided evidence for the serial position effect in terrestrial snails, suggesting conserved memory mechanisms across diverse species.
• The study demonstrates the utility of Pavlovian conditioning in understanding invertebrate cognition and memory.