BEHAVIORAL AND BRAIN SCIENCES (2011) 34,1–56 doi:10.1017/S0140525X10001354 The evolution and psychology of self-deception William von Hippel School of Psychology, University of Queensland, St Lucia, QLD 4072, Australia [email protected] http://www.psy.uq.edu.au/directory/index.html?id¼1159 Robert Trivers Department of Anthropology, Rutgers University, New Brunswick, NJ 08901 [email protected] http://anthro.rutgers.edu/ index.php?option¼com_content&task¼view&id¼102&Itemid¼136 Abstract: In this article we argue that self-deception evolved to facilitate interpersonal deception by allowing people to avoid the cues to conscious deception that might reveal deceptive intent. Self-deception has two additional advantages: It eliminates the costly cognitive load that is typically associated with deceiving, and it can minimize retribution if the deception is discovered. Beyond its role in specific acts of deception, self-deceptive self-enhancement also allows people to display more confidence than is warranted, which has a host of social advantages. The question then arises of how the self can be both deceiver and deceived. We propose that this is achieved through dissociations of mental processes, including conscious versus unconscious memories, conscious versus unconscious attitudes, and automatic versus controlled processes. Given the variety of methods for deceiving others, it should come as no surprise that self-deception manifests itself in a number of different psychological processes, and we discuss various types of self-deception. We then discuss the interpersonal versus intrapersonal nature of self-deception before considering the levels of consciousness at which the self can be deceived. Finally, we contrast our evolutionary approach to self-deception with current theories and debates in psychology and consider some of the costs associated with self-deception. Keywords: deception; evolutionary psychology; motivated cognition; self-deception; social psychology Why would people deceive themselves? What is the mental others, they can also be useful in deceiving the self. architecture that enables the same person to be both decei- For example, if I can deceive you by avoiding a critical ver and deceived? How does self-deception manifest itself piece of information, then it stands to reason that I can psychologically? And how do these three questions interre- deceive myself in the same manner. Thus, we consider late? In this article we address these issues with an evol- various types of self-deception, including biased infor- utionary account of self-deception, according to which mation search strategies, biased interpretive processes, self-deception evolved to facilitate deception of others. and biased memory processes. What marks all of these var- First, we define what we mean by self-deception and ieties of self-deception is that people favor welcome over describe how self-deception serves the goal of interpersonal unwelcome information in a manner that reflects their deception. We then discuss the non-unitary nature of the goals or motivations (in this sense, our approach to self- mind and how different types of psychological dualism deception is consistent with Kunda 1990; Mele 1997; enable the same person to be both deceiver and deceived. Pyszczynski & Greenberg 1987). We also consider classic Next we describe different varieties of self-deception cases of self-deception such as rationalization and convin- and the evidence for these different varieties. We then cing the self that a lie is true. discuss the interpersonal versus intrapersonal nature of self-deception before considering the levels of conscious- ness at which the self can be deceived. Finally, we contrast our evolutionary approach to self-deception with current WILLIAM VON HIPPEL, professor of psychology at the theories and debates in psychology. University of Queensland, Australia, conducts research in social cognition and evolutionary psychology. 1. Deception and self-deception ROBERT TRIVERS, professor of anthropology at Rutgers University, is best known for his theories of reciprocal There are many ways to deceive other people. An obvious altruism, parental investment and sexual selection, par- ental control of offspring sex ratio, and parent–offspring choice is to tell an outright lie, but it is also possible to conflict. Trivers is recipient of the Crafoord Prize for deceive others by avoiding the truth, obfuscating the “his fundamental analysis of social evolution, conflict truth, exaggerating the truth, or casting doubt on the and cooperation.” truth. Just as these processes are useful in deceiving # Cambridge University Press 2011 0140-525X/11 $40.00 1 von Hippel & Trivers: The evolution and psychology of self-deception Our approach consists of treating self-deception as a biases can reflect cognitive shortcuts, errors, and differen- variety of different processes that are directly comparable tial weighting of prior and new information that have to those involved in interpersonal deception. This nothing to do with motivational concerns (e.g., Chambers approach has the advantage of tying self-deception to pro- & Windschitl 2004). From our perspective, biases in infor- cesses that have been studied in interpersonal deception. mation processing can be considered self-deceptive only But it has the disadvantage that some behaviors are ambig- when they favor welcome over unwelcome information uous concerning whether they should be classified as self- in a manner that reflects the individual’s goals. For deception. This sort of ambiguity arises to the same degree, example, if bolstering a person’s self-image makes that however, in the study of interpersonal deception. For individual more willing to search out negative information example, consider a man who has returned home late about himself (Trope & Neter 1994), we have some evi- from work because he stopped to talk to a female colleague dence that prior avoidance of negative information about and who is confronted by his wife, who wants to know why the self was motivated and self-deceptive. Similarly, if he is late. If he responds by claiming his boss gave him an people spend more time learning about the negative extra assignment, then he is clearly being deceptive. If he than the positive features of someone else only when responds by saying that he stopped to talk to this female they expect that person will reject them (Wilson et al. colleague, then he is clearly being truthful. But if he 2004), we again have some evidence that focusing on the changes the subject – perhaps by saying that dinner negative aspects of another was motivated and self-decep- smells great – and thereby distracts his wife from her tive. But if biases are impervious to such manipulations or line of inquiry, then it is not clear whether he was deceptive irrelevant to such concerns, then the evidence suggests or simply failed to answer the question. There is no way to that they are not self-deceptive. For example, people know if he is deceiving his wife (by avoiding the truth) often rely on peripheral cues such as source expertise without knowing his intent in changing the subject or when processing arguments about issues that do not without knowing more about the relationships among concern them (Petty & Cacioppo 1986). Such biases do him, his wife, and his colleague. In the same manner, not reflect self-deception, but rather are simply evidence when people avoid unpleasant truths in their own lives, it that these individuals are insufficiently motivated to is often impossible to know if self-deception or some study the arguments carefully and are satisfied to rely on other process is at work without knowing more about a heuristic that experts tend to be correct. We return to their motives or situations. Nevertheless, just as interperso- this issue of differentiating self-deceptive from non-self- nal deception can be studied in the absence of complete deceptive biases in section 5. confidence in all classifications, self-deception can also be studied despite the inevitability of such ambiguous cases. Our approach of treating self-deception as information- 2. Self-deception in the co-evolutionary struggle processing biases that give priority to welcome over unwel- between deceiver and deceived come information also differs from classic accounts that hold that the self-deceiving individual must have two sep- If (as Dawkins argues) deceit is fundamental in animal com- munication, then there must be strong selection to spot decep- arate representations of reality, with truth preferentially tion and this ought, in turn, select for a degree of self- stored in the unconscious mind and falsehood in the con- deception, rendering some facts and motives unconscious so scious mind (see Gur & Sackeim 1979). As is clear in our as to not betray – by the subtle signs of self-knowledge – the review of information-processing biases in section 5, deception being practiced. Thus, the conventional view that people can deceive themselves by preventing unwanted natural selection favors nervous systems which produce ever information from being encoded in the first place. This more accurate images of the world must be a very naı¨ve view act can be demonstrably motivational, for example, if of mental evolution. (Trivers 1976/2006, p. 20) people stop gathering information when they like the In the struggle to accrue resources, a strategy that has early returns but keep gathering more information when emerged over evolutionary time is deception. For they do not (Ditto & Lopez 1992). The flexible nature of example, people frequently lie to those on whom they this information-gathering bias also reveals that people are dependent to receive resources that might not other- have some awareness that upcoming information may be wise be provided (DePaulo & Kashy 1998; Steinel & De inconsistent with what they have already discovered. Dreu 2004). Indeed, approximately half of people’s daily Thus, biases of this sort are consistent with classic defi- deceptions are intended to gain a resource for the self nitions of self-deception that emphasize simultaneous (DePaulo & Kashy 1998).