A non-human primate test of abstraction and set shifting: An automated adaptation of the Wisconsin Card Sorting Test

Functional assessment of the prefrontal cortices in the non-human primate began with the seminal work of Jacobsen in the 1930s. However, despite nearly 70 years of research, the precise nature of the cognitive function of this region remains unclear. One factor that has limited progress in this endeavor has been the lack of behavioral tasks that parallel most closely those used with humans. In the present study, we describe a test for the non-human primate that was adapted from the Wisconsin Card Sorting Task (WCST), perhaps the most widely used test of prefrontal cognitive function in humans. Our adaptation of this task, the Conceptual Set-Shifting Task (CSST), uses learning criteria and stimuli nearly identical to those of the WCST. The CSST requires the animal to initially form a concept by establishing a pattern of responding to a given stimulus class, maintain responding to that stimulus class, and then shift to a different stimulus class when the reward contingency changes. The data presented here establishes baseline performance on the CSST for young adult rhesus monkeys and demonstrates that components of prefrontal cognitive function can be effectively assessed in the non-human primate in a manner that parallels the clinical assessment of humans.