Figure 5. Sketch of baited boxes in both training steps.

Grey items display the food reward, A indicates the actor side. Arrows describe the only direction in which the boxes could be opened: only by the actor and to the actor's side. Bold lines above, between, and below the drafted boxes illustrate the dividing wire mesh between test compartments while intermediate thin lines illustrate the transparent partitions within boxes. Distance between the boxes is not to scale. a) represents training step 1, with the 0/0 option on top and the 1/1 option below. b) represents training step 2, with the 1/0 option on top and the 0/1 option below.