Learning of spatial statistics in nonhuman primates: contextual cueing in baboons (Papio papio).

A growing number of theories of cognition suggest that many of our behaviors result from the ability to implicitly extract and use statistical redundancies present in complex environments. In an attempt to develop an animal model of statistical learning mechanisms in humans, the current study investigated spatial contextual cueing (CC) in nonhuman primates. Twenty-five baboons (Papio papio) were trained to search for a target (T) embedded within configurations of distrators (L) that were either predictive or non-predictive of the target location. Baboons exhibited an early CC effect, which remained intact after a 6-week delay and stable across extensive training of 20,000 trials. These results demonstrate the baboons' ability to learn spatial contingencies, as well as the robustness of CC as a cognitive phenomenon across species. Nevertheless, in both the youngest and oldest baboons, CC required many more trials to emerge than in baboons of intermediate age. As a whole, these results reveal strong similarities between CC in humans and baboons, suggesting similar statistical learning mechanisms in these two species. Therefore, baboons provide a valid model to investigate how statistical learning mechanisms develop and/or age during the life span, as well as how these mechanisms are implemented in neural networks, and how they have evolved throughout the phylogeny.