REWARD AND LEARNING IN HONEYBEES - ANALYSIS OF AN OVERSHADOWING EFFECT

Previous experiments have shown that honeybees trained with colored ta rgets baited with 5 versus 20-mu l drops of sucrose solution fail to d evelop a preference for the 20-mu l color when the location of the dro p on each target is marked by a white dot (dot-color overshadowing) bu t that discrimination is not impaired by dots when the targets differ in odor rather than in color. In Experiments 1-3, dot-color overshadow ing failed to appear with differences in concentration rather than amo unt of sucrose (50% vs. 20% or 0%), but it did appear in Experiments 4 and 5 with a difference in probability of reward (consistent vs. part ial). Experiment 6 showed no dot-odor overshadowing with a difference in probability of reward. The results are not generally predictable fr om the Rescorla-Wagner principle of shared associative strength, but p oint instead (in conjunction with those of earlier experiments) to com petition for visual attention.