Same/Different Concept Learning and Category Discrimination in Honeybees.

Abstract

Honeybees show a variety of associative learning phenomena with performance resembling that of vertebrates. This research explores the cognitively-complex phenomena of same/different concept learning and category discrimination. The free-flying procedure was used in all of the experiments. Foraging honeybees were trained individually to fly between the hive and the laboratory for sucrose reward. In Experiment 1, honeybees were trained in a four-stimulus oddity problem with two-color pattern stimuli that were unique on every trial. They were rewarded for choosing the odd stimulus on every trial and learned to choose correctly. In Experiment 2, four groups of honeybees were trained in a simultaneous same/different discrimination with a pair of identical patterns (same) and a pair of nonidentical patterns (different), again, with trial-unique training. Two groups were rewarded for choosing same, and two for choosing different. The results are the first to demonstrate same/different discrimination learning in honeybees. In Experiments 3 and 4, bees were trained to discriminate a pair of patterns from a pair of solid colors, with unique sets on every trial. In Experiment 3, the stimuli in the pairs were identical, and in Experiment 4, the stimuli in the pairs were nonidentical. Half the bees were rewarded for choosing solids, and half for choosing patterns. The bees easily discriminated the pairs, suggesting they formed categories of solids and patterns. Experiment 5 was like Experiment 1 but with a category dimension added to the four-stimulus oddity. On half the trials, the stimuli were a pattern and three identical solids, and on the others, a solid and three identical patterns. The bees choose correctly and the category dimension enhanced performance. Experiment 6 was like Experiment 2 but with a category dimension added to the same/different discrimination. On half the trials, the same pair was two solids and the different pair two patterns, and on the others, the same pair was two patterns and the different pair two solids. One group was rewarded for choosing same, and the other for choosing different. Both groups solved the discrimination. This set of experiments provides evidence of same/different concept learning and category discrimination in honeybees.