Authors: Julie Benard Martin Giurfa
Publish Date: 2007/10/23
Volume: 11, Issue: 2, Pages: 283-293
Abstract
Generalization occurs when a conditioned response formed to one stimulus is also elicited by other stimuli which have not been used in the course of conditioning Here we studied color generalization in honeybees Apis mellifera trained to two rewarded colors S1+ and S2+ After training bees were tested with nonrewarded novel stimuli which lay between the trained stimuli in a honeybee color space Int or outside the range defined by the trained stimuli E 1 and E 2 We analyzed whether bees interpolated their choice to Int and/or extrapolated it to E 1 and E 2 We compared the performances of the group trained with S1+ and S2+ to those of control groups trained only with S1+ or S2+ Bees trained with S1+ and S2+ responded similarly and highly to all test stimuli These results do not allow discerning between generalization models based on the presence of interpolation and/or extrapolation Nevertheless bee’s performance was consistent with a linear summation of the two generalization gradients generated by S1+ and S2+ respectively These gradients were asymmetric because control bees responded to the test stimuli as if these belonged to different similarity classes in spite of the fact that they had similar perceptual distances separating them Stimuli treated as similar were located in the same half of the color spaces whereas stimuli treated as different were located in opposite halves Our results suggest that color categories could exist in honeybees and may underlie the performance of the control groups Under this assumption color categories would be also present in simpler nervous systems and would not require factors such as language to be expressedThanks are due to T Czeschlik and three anonymous referees for useful comments on the manuscript We also thank W Farina and his team at the University of Buenos Aires for much help during the experiments This work was supported by the French National Research Center Research CNRS and the University Paul Sabatier of Toulouse
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