Tactical Deception By Capuchin Monkeys?

Primatologist Brandon Wheeler, from Stony Brook University, New York, set up an experiment, using platforms baited with food, to test the idea that subordinate individuals utter a certain type of distress call with the intention to deceive dominants that danger had been spotted - thereby alerting them to leave the area, leaving the path to food open. But, of course, the ever-present problem with observations of "tactical deception" in the wild continues to bug this kind of research. In order to tactically deceive the deceiver must know that he is seeding a false belief in the mind of another. How can you prove it? There is always stress evoked in competition for food, and this stress naturally evokes what Wheeler calls resource-related stress calls. Simple association could do the rest. The subordinate monkey could simply learn that other monkeys tend to be scared away from food whenever it utters these distress calls. Their apparently deceptive behaviour would then not be intentional in any way.