Relational learning in honeybees (Apis mellifera): Oddity and nonoddity discrimination.

Honeybee learning is surprisingly similar to vertebrate learning and one implication is that the basic associative learning principles are also similar. This research extends the work to more complex cognitive phenomena. Forager bees were trained individually to visit a laboratory window for sucrose. On each training trial for all experiments, bees found three stimuli, two identical and one different. In Experiments 1 and 2, stimuli were three-dimensional two-color patterns, and in Experiments 3 and 4, stimuli were two-color patterns displayed on a computer monitor. Training was trial-unique, that is, a different triad of stimuli was presented on each trial. In Experiments 1 and 3, choice of odd was rewarded and choice of nonodd was punished. In Experiments 2 and 4, choice of nonodd was rewarded and choice of odd was punished. On every trial, the initial choice was recorded and correction permitted. Honeybees learned to choose the odd stimulus in Experiments 1 and 3 and the nonodd stimuli in Experiments 2 and 4. The results provide compelling evidence of oddity and nonoddity learning, often interpreted as relational learning in vertebrates. Whether the mechanism of such learning in honeybees is similar to that of vertebrate species remains to be determined.