Tactical Deception is Evidence of Cognitive Evolution in Primates?

W. Byrne and A. Whiten hypothesized that evidence of tactical deception led to the cognitive evolution in primates. By using an array of an elaborate catalog of tactical deception provided by many primatologists in primates that covers all major taxa of primates, they found that Papio and Panexpress high levels of tactical deception, while strepsirrhines do not show any deception. Because of this tactical deception, some studies have implied that this is due to higher social cognition in the great apes. Many people have tried to explain cognition in primates by performing gadgetry type experiments which do not correlate with the what the primate actually encounters in their everyday lives. But Byrne and Whiten are going off of the Machiavellian intelligence (social brain) hypothesis that large brains/cognitive abilities have evolved due to intense social competition. This study looks at the different taxa of primates and their abilities to deceive others and how that is connected to the evolution of primate cognition.

By comparing abilities from extant species to common ancestors, an ability will be passed down unless it becomes unfavorable towards natural selection. Acts of deception are great indicators because they involve other primates. Because of this manipulation/ deception, a primate can remember and retaliate which indicates higher intelligence. They defined tactical deception as “acts from the normal repertoire of the agent, deploying such that another individual is likely to misinterpret what the acts signify, to the advantage of the agent.” Byrnes and Whiten used observational data collected from other studies to figure out if tactical deception occurred because no studies had been down on tactical deception. They sent out 1 survey asking informants to report any behaviors that matched their definition. From peer feedback, they edited their definition and sent out a second survey that reached a farther range of people. They tried to standardize their request when sending out surveys. There were 253 records of primate behavior that fulfilled their definition of tactical deception. The records are organized taxonomically and by the type of deception: concealment, distraction, attraction, creating an image, deflection using a social tool, and counter-deception. The records were further categorized based on the level of evidence and observer-category. Throughout Byrnes and Whiten’s analysis, they tried to take into account all the biases and other confounding variables that could have affected the results of the analysis.

In conclusion, they found that Papio and Pan species of primates show tactical deception while lemur’s do not show any deception. In addition, there is an absence of deception within the strepsirrhines. Before the analysis, Byrne and Whiten made predictions about the number of observed tactical deceptions made, and they found that most of them were accurate given the data collected so far except in the case of Papio and Pan species. They also found that in the great apes they are capable of recognizing intentional states of others which may indicate higher cognition. Even though Byrne and Whiten try to take sampling bias into consideration, it is still hard to stop scientists from having their own opinions on certain primates. From this study, they have learned that it is hard to study cognition and that there still needs to be more studies/ experiments done to figure out a good way to actually access intelligence in non-human animals. In addition, the idea of brain size and body size does not always answer the question of higher cognitive ability in non-humans.

Byrne, R., & Whiten, A. (1992). Cognitive Evolution in Primates: Evidence from Tactical Deception. Man, 27(3), new series, 609-627. doi:10.2307/2803931