A test of transitive inferences in free-flying honeybees: unsuccessful performance due to memory constraints.
We asked whether honeybees, Apis mellifera, could solve a transitive inference problem. Individual free-flying bees were conditioned with four overlapping premise pairs of five visual patterns in a multiple discrimination task (A+ vs. B-, B+ vs. C-, C+ vs. D-, D+ vs. E-, where + and - indicate sucrose reward or absence of it, respectively). They were then tested with the nonadjacent pairs A vs. E and B vs. D. Preference of B to D is consistent with the use of the implicit hierarchy A > B > C > D > E. Equal choice of B and D supports choice based on the associative strength of the stimuli. The bees' choice was determined by their memory constraints: experience with the last premise pair (D+ vs. E-) predominated. In the tests, bees preferred A to E and chose equally B and D. An analysis of the performance in terms of a reward/penalty ratio showed that B had a higher associative strength than D. Thus, bees do not establish transitive inferences but, rather, guide their choices by the joint action of a recency effect and the associative strength of the stimuli. The former supports choice of D, whereas the latter supports choice of B, thus determining equal choice of B and D in the tests.
Benard
Julie
J
Centre de Recherches sur la Cognition Animale, CNRS-Université Paul-Sabatier (UMR 5169), 31062 Toulouse cedex 04, France.
Giurfa
Martin
M
D000818:Animals; D001245:Association Learning; D001516:Bees / Q000502:physiology*; D002755:Choice Behavior; D004193:Discrimination Learning / Q000502:physiology*; D005426:Flight, Animal / Q000502:physiology; D018782:Maze Learning / Q000502:physiology*; D008568:Memory; D011340:Problem Solving; D013037:Spatial Behavior