Bumble bee visual learning: simple solutions for complex stimuli

Natural visual stimuli are typically complex. This presents animals with the challenge of learning the most informative aspects of these stimuli while not being confused by variable elements. How animals might do this remains unclear. In this study, we tested bumble bees’ ability to learn multicomponent visual stimuli composed of a simple constant bar element and a grating element that was consistent in orientation but varied in width, number of gratings and position. Bees rapidly and successfully learnt these compound stimuli. Tests revealed learning of the consistent single bar was more robust than learning of the grating element. This study highlights how even small-brained invertebrates can rapidly learn multicomponent stimuli and prioritize the most consistent elements within them. We discuss how the learning phenomena of generalization and overshadowing may be sufficient to explain these findings, and caution that complex cognitive concepts are not necessary to explain the learning of complex stimuli.