Peek a boo! Information seeking about food and functionality in capuchin monkeys.

The ability to be aware of your own knowledge state (metacognition) can be investigated by examining an individual's information-seeking behaviour. Chimpanzees (Pan troglodytes) perform strategic searches for food and tools. However, although capuchin monkeys (Sapajus apella) seek information about food, whether they search for functional information is unknown. Further, if information seeking indicates awareness of what knowledge is missing, rather than an uncertainty response, search patterns should reflect the missing information. We presented 12 capuchin monkeys with two novel information seeking tasks; Experiments 1 and 2 investigated their food search, Experiment 3 investigated their search for functionality. In both tasks information could be sought from two locations; looking below a barrier provided information about food, looking above a barrier provided information about food in Experiments 1 and 2 or cup functionality (open or sealed) in Experiment 3. Monkeys were trained to select the target cup with all information visible. Then we occluded the cups and presented the monkeys with different configurations of missing information requiring looks above, below, or both to locate the target cup. When searching for both food and functional information the monkeys' searching was selective; it was more likely under occluded conditions. However, search location was not significantly affected by different configurations of missing information, suggesting they were not tailoring their information seeking. This supports previous findings that capuchins perform information-seeking to fill knowledge gaps. However, we found no evidence that searching was sensitive to the information was required. We conclude that capuchin monkeys show selective but not strategic information seeking.