Machiavellian Intelligence Hypothesis

The Machiavellian intelligence hypothesis takes several forms, but all stem from the proposition that the advanced cognitive processes of primates are primarily adaptations to the special complexities of their social lives, rather than to nonsocial environmental problems such as finding food, which were traditionally thought to be the province of intelligence. The new "social" explanation for the evolution of INTELLIGENCE arose in the context of proliferating field studies of primate societies in the 1960s and 1970s. The paper generally recognized as pivotal in launching this wave of studies was Nicholas Humphrey's "The Social Function of Intellect" (1976), the first to spell out the idea explicitly, although important insights were offered by earlier writers, notably Alison Jolly (see Whiten and Byrne 1988a for a review). By 1988 the idea had inspired sufficient interesting empirical work to produce the volume Machiavellian Intelligence (Byrne and Whiten 1988; now see also Whiten and Byrne 1997), which christened the area.

The Machiavellian intelligence hypothesis has been recognized as significant beyond the confines of primatology, however. On the one hand, it is relevant to all the various disciplines that study human cognitive processes. Because the basic architecture of these processes is derived from the legacy of our primate past, a more particular Machiavellian subhypothesis is that developments in specifically human intelligence were also most importantly shaped by social complexities. On the other hand, looking beyond primates, the hypothesis has been recognized as of relevance to any species of animal with sufficient social complexity.

Why "Machiavellian" intelligence? Humphrey talked of "the social function of intellect" and some authors refer to the "social intelligence hypothesis" (Kummer et al. 1997). But "social" is not really adequate as a label for the hypothesis. Many species are social (some living in much larger groups than primates) without being particularly intelligent; what is held to be special about primate societies is their complexity, which includes the formation of sometimes fluid and shifting alliances and coalitions. Within this context, primate social relationships have been characterized as manipulative and sometimes deceptive at sophisticated levels (Whiten and Byrne 1988b). Primates often act as if they were following the advice that Niccolo Machiavelli offered to sixteenth-century Italian prince-politicians to enable them to socially manipulate their competitors and subjects (Machiavelli 1532; de Waal 1982). "Machiavellian intelligence" therefore seemed an appropriate label, and it has since passed into common usage.

An important prediction of the hypothesis is that greater social intellect in some members of a community will exert selection pressures on others to show greater social expertise, so that over evolutionary time there will be an "arms race" of Machiavellian intelligence. Indeed, one of the questions the success of the hypothesis now begins to raise is why such escalation has not gone further than it has in many species.

But the way in which the hypothesis highlights competitive interactions must not be interpreted too narrowly. "Machiavellianism" in human affairs is often taken to include only a subset of social dealings characterized by their proximally selfish and exploitative nature (Wilson, Near, and Miller 1996). Although animal behavior is expected to be ultimately selfish in the face of natural selection (by definition a competition), COOPERATION with some individuals against others can be one means to that end. Primate coalitions provide good examples. Indeed, because an important component of exploiting one's social environment includes learning socially from others, primate "culture" also comes within the scope of Machiavellian intelligence.

As noted at the outset, the Machiavellian hypothesis is not so much a single hypothesis as a cluster of related hypotheses about the power of social phenomena to shape cognitive processes. Two main variants may be distinguished here. In one version of the hypothesis, intelligence is seen as a relatively domain-general capacity, with degrees of intelligence in principle distinguishable among different taxa of animals. In this case, the hypothesis proposes that different grades of intelligence will be correlated significantly and most closely with variations in the social complexity of the taxa concerned. This should apply to any taxon with the right kind of social complexity. Although primate research was the arena from which the ideas sprang, related kinds of complexity are now being described in other taxa, like the alliances of dolphins and hyenas (Harcourt and de Waal 1992).

Another version of the hypothesis proposes that the very nature of the cognitive system will be shaped to handle social phenomena: a domain-specific social intelligence (see DOMAIN SPECIFICITY). This possibility has been examined in both human and nonhuman primates, with the bulk of work done on humans. Influential research includes the work of Cosmides (1989) on the power of cheater detection mechanisms to handle logical problems humans find difficult in equivalent nonsocial contexts (see EVOLUTIONARY PSYCHOLOGY). Another well-documented case is our everyday THEORY OF MIND, whose social domain specificity is highlighted by autistic individuals' difficulty in reading other minds, despite high levels of nonsocial intelligence (Baron-Cohen 1995; see AUTISM). For nonhuman primates, Cheney and Seyfarth (1990) report the results of both observational and experimental studies in which vervet monkeys demonstrate social expertise in excess of that operating in equivalent nonsocial contexts. For example, the monkeys may discriminate as targets of aggression those individuals whose kin have fought their own kin, yet fail to read the signs of a recent python track entering a bush (see SOCIAL COGNITION IN ANIMALS).

A different kind of test of the Machiavellian hypothesis is based on examining the correlates of relative brain size across primate and other animal taxa. Contrary to some earlier findings, the strongest predictors of encephalization that have emerged consistently in recent studies are not measures of physical ecological complexity such as home range size, but the size of the social group or clique, an indicator (even if a crude one) of social complexity (Dunbar 1995; Barton and Dunbar 1997). Although this approach conflates the two alternative versions of the hypothesis discriminated above (because we do not know how modular the mechanisms are that contribute to greater encephalization) the results obviously support the Machiavellian intelligence hypothesis in the general form stated at the start of this entry.

See also

Additional links

-- Andrew Whiten


Baron-Cohen, S. (1995). Mindblindness: An Essay on Autism and Theory of Mind. Cambridge, MA: The MIT Press.

Barton, R. A., and R. I. M. Dunbar. (1997). Evolution of the social brain. In A. Whiten and R. W. Byrne, Eds., Machiavellian Intelligence. Vol. 2, Evaluations and Extensions. Cambridge: Cambridge University Press, pp. 240-263.

Byrne, R. W., and A. Whiten. (1988). Machiavellian Intelligence: Social Expertise and the Evolution of Intellect in Monkeys, Apes and Humans. Oxford: Oxford University Press.

Cheney, D. L., and R. M. Seyfarth. (1990). How Monkeys See the World: Inside the Mind of Another Species. Chicago: University of Chicago Press.

Cosmides, L. (1989). The logic of social exchange: Has natural selection shaped how humans reason? Studies with the Wason selection task. Cognition 31:187-276.

de Waal, F. (1982). Chimpanzee Politics. London: Cape.

Dunbar, R. I. M. (1995). Neocortex size and group size in primates: A test of the hypothesis. Journal of Human Evolution 28:287-296.

Harcourt, A. H., and F. B. deWaal. (1992). Coalitions and Alliances in Humans and Other Animals. Oxford: Oxford University Press.

Humphrey, N. K. (1976). The social function of intellect. In P. P. G. Bateson and R. A. Hinde, Eds., Growing Points in Ethology. Cambridge: Cambridge University Press, 1976, pp. 303-321.

Kummer, H., L. Daston, G. Gigerenzer, and J. Silk. (1997). The social intelligence hypothesis. In P. Weingart, P. Richerson, S. D. Mitchell, and S. Maasen, Eds., Human by Nature: Between Biology and the Social Sciences. Hillsdale, NJ: Erlbaum, pp. 157-179.

Machiavelli, N. (1532). The Prince. Harmondsworth, England: Penguin, 1961.

Whiten, A., and R. W. Byrne. (1988a). The Machiavellian intellect hypotheses. In R. W. Byrne and A. Whiten, Eds., Machiavellian Intelligence. Oxford: Oxford University Press, pp. 1-9.

Whiten, A., and R. W. Byrne. (1988b). Tactical deception in primates. Behavioral and Brain Sciences 11:233-273.

Whiten, A., and R. W. Byrne. (1997). Machiavellian Intelligence. Vol. 2, Evaluations and Extensions. Cambridge: Cambridge University Press.

Wilson, D. S., D. Near, and R. R. Miller. (1996). Machiavellianism: A synthesis of the evolutionary and psychological literatures. Psychological Bulletin 119:285-299.

Further Readings

Brothers, L. (1990). The social brain: A project for integrating primate behavior and neurophysiology in a new domain. Concepts in Neuroscience 1:27-51.

Byrne, R. W. (1995). The Thinking Ape: Evolutionary Origins of Intelligence. Oxford: Oxford University Press.

Byrne, R. W., and A. Whiten. (1990). Tactical deception in primates: The 1990 database. Primate Report 27:1-101.

Crow, T. J. (1993). Sexual selection, Machiavellian intelligence, and the origins of psychosis. Lancet 342:594-598.

Dunbar, R. I. M. (1992). Neocortex size as a constraint on group size in primates. Journal of Human Evolution 20:469-493.

Erdal, D., and A. Whiten. (1996). Egalitarianism and Machiavellian intelligence in human evolution. In P. Mellars and K. Gibson, Eds., Modelling the Early Human Mind. Cambridge, England: McDonnell Institute, pp. 139-150.

Sambrook, T., and A. Whiten. (1997). On the nature of complexity in cognitive and behavioural science. Theory and Psychology 7:191-213.

Venables, J. (1993). What is News? Huntingdon, England: ELM.

Whiten, A. (1991). Natural Theories of Mind: Evolution, Development and Simulation of Everyday Mindreading. Oxford: Blackwell.

Whiten, A. (1993). Deception in animal communication. In R. E. Asher, Ed., The Pergamon Encylopedia of Language and Linguistics, vol. 2. Pergamon Press, pp. 829-832.

Whiten, A. (1996). Imitation, pretence and mindreading: Secondary representation in comparative primatology and developmental psychology. In A. Russon, K. A. Bard, and S. T. Parker, Eds., Reaching into Thought: The Minds of the Great Apes. Cambridge University Press, pp. 300-324.

Whiten, A. (Forthcoming). Primate culture and social learning. Cognitive Science .