Executive control of perceptual features and abstract relations by baboons (Papio papio).

Studies of executive control often reveal significant limitations in nonhuman primate performance relative to that of humans. In the present study, 24 socially housed baboons were tested on a computerized version of the Wisconsin Card Sorting Task (WCST) to assess individual differences in executive control. In a second experiment, the same baboons completed a version of the WCST with paired-relational stimuli rather than those that varied on a single dimension to evaluate their set-shifting abilities with abstract relations (same/different). All baboons completed the required shifts on the traditional WCST, but only 12 baboons succeeded in making relational shifts. Age was found to be a significant factor in the level of success on both tasks with younger baboons (mean age 4 years) outperforming older, albeit not aged, baboons (mean age 11.5 years). These results implicate an earlier decline in executive control processes for nonhuman primates with more pronounced effects for cognitive flexibility of abstract relations.