International Journal of Comparative Psychology

Two bonobos ( Pan paniscus ) and three chimpanzees ( P. troglodytes ) monitored spatial transpositions, or the simultaneous movement of multiple items in an array, so as to select a specific item from the array. In the initial condition of Experiment 1, food reward was hidden beneath one of four cups, and the apes were required to select the cup containing the reward in order to receive it. In the second condition, the test board on which the cups were located was rotated 180 degrees after placement of the food reward. In the third condition, two of the three cups switched locations with one another after placement of the food reward. All five apes performed at very high levels for these conditions. Experiment 2 was a computerized simulation of the tasks with the cups in which the apes had to track one of four simultaneously moving stimuli on a computer monitor. Two of the three apes that were tested performed at a very high level for this computerized task. Therefore, members of the genus Pan can perform complex feats of spatial monitoring such as transpositions both in real world contexts and in computerized tests.