Results of Experiment 1: Does quinine improve visual discrimination of perceptually dissimilar colors when used as negative reinforcer?

<p>(A) Plots of colored stimuli used in experiment 1 in a COC color space (left) and hexagon color space (right) for the trichromatic vision of honeybees. The colour distances between stimuli are above 2.5 COC units and above 0.2 hexagon units. Numbers refer to the HKS papers references. (B) Learning acquisition (correct choices (%) by blocks of 5 trials; means ± s.e.m.; N = 9 for each curve). The curve with black dots represents acquisition by the quinine group (CS− reinforced with quinine); the curve with white dots represents acquisition by the water group (CS− reinforced with water). (C) Performance (means + s.e.m. of percentages of CS+ choices (‘learning’ and ‘appetitive’ test) or CS− choices (‘aversive’ test); N = 9 for each bar) in non-rewarded tests. Black bars represent the results of the quinine group; white bars represent the results of the water group. The learning performance in this easy colour discrimination task was not significantly different between test groups. Bees from the quinine groups avoided the stimulus associated with quinine during training when proposed versus a neutral stimulus, however this avoidance was not found in the water group (**: p&lt;0.005).