Metacognitive-like information seeking in lion-tailed macaques: a generalized search response after all?

Previous research has demonstrated that Old World primates (both apes and monkeys) seek information about the location of a hidden food item, unless they are privy to the hiding process. This has been cited as evidence of metacognition. However, these results could also be interpreted using non-metacognitive accounts, including a generalized search response to uncertainty, in which subjects reach for food when it is seen, or search for food until it is spotted. In the present research, lion-tailed macaques were tested on an object-choice task. Conditions varied with respect to the visibility of the baiting process, and whether the location of the hidden food could be inferred by logical exclusion. Additionally, the hidden food could be located visually before a choice was made, by peering under the objects through a Plexiglas tray. Across conditions, monkeys consistently looked for the food when it had not been seen, even if its location could be inferred, despite the fact that these monkeys are capable of inference by exclusion. This suggests that apparently 'metacognitive' information seeking in monkeys may instead reflect a generalized search strategy. Alternatively, it is possible that monkeys only have metacognitive access to certain types of knowledge, including that obtained visually. Results are discussed with respect to the likelihood of metacognition in this species and the evolutionary emergence of metacognition across species.