Different-but-Similar Judgments by Bumblebees

Abstract

This study examines picture perception in an invertebrate. Two questions regarding possible picture-object correspondence are addressed for bumblebees (Bombus impatiens): (1) Do bees perceive the difference between an object and its corresponding picture even when they have not been trained to do so? (2) Do they also perceive the similarity? Twenty bees from each of four colonies underwent discrimination training of stimuli placed in a radial maze. Bees were trained to discriminate between two objects (artificial flowers) in one group and between photos of those objects in another. Subsequent testing on unrewarding stimuli revealed, for both groups, a significant discrimination between the object and its photo: discrimination training was not necessary for bees to detect a difference between corresponding objects and pictures. We obtained not only object-to-picture transfer, as in previous research, but also the reverse: picture-to-object transfer. In the absence of the rewarding object, its photo, though never seen before by the bees, was accepted as a substitute. The reverse was also true. Bumblebees treated pictures as “different-but-similar” without having been trained to do so, which is in turn useful in floral categorization.

Keywords

• Bumblebees
• Picture-object correspondence
• Similarity judgment
• Categorization