Unlocking the Chimpanzee Mind: An Investigation of Chimpanzee Cognitive Capability
by Wade Kothmann
Two perspective-taking paradigms that have shown great promise in theory of mind research with nonhuman primates, but which have not yielded any significant results, are the “seeing and knowing” and “seeing and attending” paradigms (Heyes, 1998). The present study notes that each of these paradigms makes the assumption that chimpanzees can make a discrimination between a human experimenter who can “see” and one who cannot “see,” and offers that this may not be a valid assumption. Fourteen chimpanzees above the age of eighteen years were trained in a modified stimulus discrimination task to choose one of two mannequin heads. Half were trained to choose a head with its eyes painted open, while the other half were trained to choose a head with its eyes painted shut. The training was divided into four distinct stages. At present all fourteen subjects have progressed through pre-training and into stage two of the training, and two of these have progressed into stage three of training. Preliminary data analysis indicates extensive variability between subjects with regard to rate of learning. One interesting trend which has emerged is a tendency to partially learn the task, then regress to chance levels of performance, and then to begin relearning the task. However, until all data has been collected, it is impossible to say with any degree of certainty what this might be due to, or what the final results will indicate with regard to whether or not chimpanzees can learn an eyes open/eyes closed discrimination. What can be said, at present, is that there does not appear to be an innate preference to choose a mannequin with eyes open or closed, but rather that this sort of task must be learned by the chimpanzee.
Mentor: Steven J. Schapiro, Ph.D., Southwestern University and The University of Texas M. D. Anderson Cancer Center, Bastrop, TX