Date of Thesis

Spring 2019


Metacognition is the ability for one to understand what they do and do not know and to seek additional information to fill in the gaps of what they do not know in order to complete a task. Metacognition is well studied in humans, and it has also been demonstrated in several non- human primates including chimpanzees (Pan troglodytes) and macaques (Macaca mulatta), two Old World species. The ability for capuchins (Cebus [Sapaja] apella), a New World species, to demonstrate metacognitive ability is poorly understood and previous studies led to mixed conclusions. I sought out to determine if capuchins would seek information in a token exchange task in which sometimes incomplete information was provided and the missing information needed to complete the task correctly could be sought out. I trained five capuchins to exchange a washer for a raisin reward and a bolt for an apple reward. When a single food reward was presented, the capuchins were trained to pick the token corresponding with the food reward to receive the reward. In experiment one, capuchins were tested in an information-seeking task where the identity of the food placed in a cup was the piece of critical information required to get the reward. There were trials where the food in the cup was shown to the capuchin (visible) and trials where the food reward was not shown (non-visible) prior to raising the cup so its contents could not be seen regardless of condition. The capuchins were given the option to seek information by climbing the caging to look into the container before selecting a token or immediately selecting a token without looking. The food reward was only received if the token selected was associated with the food in the cup. All capuchins were significantly more likely to look into the cup before selecting a token if they had not been shown what was inside the cup and not look when they had seen the contents of the cup. Of these five monkeys, only three have completed experiment two thus far. Experiment two controls for the possibility the monkeys are not seeking information, rather they are solely engaging in food-seeking behavior. This task used a two-cup design with a food item in each cup. The monkeys were always shown food in one cup; however, the food shown was not always the food in the raised cup. One monkey, Nye, showed behavior consistent with metacognitive ability, looking in the raised cup if he had not seen the contents in that specific cup, and not looking in the raised cup if he had seen the contents at a significantly higher rate than expected. Results indicate that capuchins are capable of information-seeking behavior consistent with metacognition. This would indicate that New World Species are also capable of metacognition.


Metacognition, Information seeking, capuchins

Access Type

Honors Thesis (Bucknell Access Only)

Degree Type

Bachelor of Science



First Advisor

Peter Judge

Second Advisor

Morgan Benowitz-Fredericks