Von Hippel & Trivers (VH&T) argue that the suite of motivated processes associated with self-deception (SD) evolved to facilitate other-deception (OD). VH&T contend that a capacity for SD may increase individuals' success in specific instances of OD by helping them conceal deception-revealing “tells,” such as those due to nervousness and cognitive load. A capacity for SD also produces self-serving biases and self-enhancement, which help individuals appear more confident and “better” to others than they really are, and thus increases one's chances of reaping interpersonal rewards. Furthermore, the optimism and happiness associated with self-serving biases and self-enhancement may produce interpersonal gains. Although it is true that downstream interpersonal benefits of a capacity for SD may increase evolutionary fitness, the immediate benefits of SD alone increase potential for reproductive success more directly. It is therefore unclear that selective pressures arising from the need to be effective at OD are necessary to explain the evolution of SD.

An ability to succeed in OD has clear benefits. Individuals who can secure undeserved resources possess a significant advantage over individuals who cannot, in terms of potential for reproductive success. To address whether a capacity for SD leads to greater effectiveness at OD in a given context, VH&T propose that researchers ought to examine whether individuals are most likely to engage in SD when they are motivated to deceive others. This test would indeed inform the discussion of whether SD assists in OD and is worthy of serious consideration. A related test is whether individuals are most likely to engage in self-enhancement on traits for which it might be particularly useful to succeed in OD. The appearance of morality is one dimension in which success in OD would be particularly helpful: If Sally can deceive Anne into thinking that Sally is moral, Anne will not only possess a generally more positive view of Sally, but Anne will also likely lower her guard against future deceptions from Sally. Deceiving others into believing that one is moral should be a useful tactic for everybody, as evidence suggests that vigilance against cheaters is a human universal (Sugiyama et al. Reference Sugiyama, Tooby and Cosmides2002). Therefore, if SD evolved in the service of OD, one might reasonably expect that all individuals self-enhance on the dimension of morality. Contrary to this prediction, people with interdependent mind-sets are less likely to self-enhance in the moral or altruistic domains than are people with independent mind-sets (Balcetis et al. Reference Balcetis, Dunning and Miller2008). This effect holds controlling for culture. This finding casts doubt on VH&T's model of SD's existence for the purpose of facilitating OD.

Considerable evidence indicates that a capacity for motivated cognition, a variety of SD, helps us to attain our goals. Objects we desire may appear larger (Bruner & Goodman Reference Bruner and Goodman1947) or closer (Balcetis & Dunning Reference Balcetis and Dunning2010) to us, and individuals predict that desired, randomly determined outcomes will occur (e.g., Babad Reference Babad1997; but see Krizan & Windschitl Reference Krizan and Windschitl2009). Such desire-biased perceptions and predictions can cause us to frame situations in terms of possible gains, making us more likely to pursue courses of action that will allow us to achieve desirable outcomes (e.g., Bandura Reference Bandura1989, p. 1177; Sternberg & Kolligan Reference Sternberg and Kolligan1990). Conversely, individuals who are motivated to avoid certain entities (such as arachnophobes toward spiders) exhibit greater vigilance for those things (Riskind et al. Reference Riskind, Moore and Bowley1995). The concrete results of our goal-oriented behaviors (e.g., food or safety, both of which were often uncertain in our evolutionary history) provide adaptive value, with interpersonal adaptive value possibly as mere epiphenomena.

VH&T argue that self-serving biases and self-enhancement cause us to be optimistic and happy. Overly positive thinking manifested as optimism and happiness contributes to good health, goal attainment, and resilience in the face of adversity (e.g., Taylor & Armor Reference Taylor and Armor1996; Taylor & Brown Reference Taylor and Brown1988). VH&T discuss optimism and happiness as possible products of SD with interpersonal benefits. Optimism, in VH&T's formulation, causes individuals to confidently persevere and occasionally succeed in difficult tasks, resulting in dividends that translate into interpersonal currency. (Underscoring optimism's adaptive value, Aspinwall and Richter (Reference Aspinwall and Richter1999), have demonstrated that optimism is also associated with abandoning an impossible task within a shorter timeframe.) VH&T point out that both optimism-driven confidence and happiness draw others to an individual, leading to greater potential for success on cooperative tasks. However, although VH&T acknowledge that sunny outlooks are associated with positive effects aside from interpersonal concerns, they discount the adaptive value of such outcomes and instead present optimism and confidence as means to interpersonal success.

Self-serving rationalizations and interpretations of our own behavior allow us to preserve our rosy views of ourselves and our prospects. Among other rationalizations, individuals reduce cognitive dissonance to uphold their views of themselves as moral and competent (e.g., Festinger & Carlsmith Reference Festinger and Carlsmith1959; Steele & Liu Reference Steele and Liu1983). Individuals from preschool-aged children to adults are motivated to rationalize even blind choices (e.g., Egan et al. Reference Egan, Bloom and Santos2010; Johansson et al. Reference Johansson, Hall, Sikstrom and Olsson2005). People engage in moral hypocrisy, whereby they convince themselves that their selfish behaviors are acceptable (e.g., Batson & Thompson Reference Batson and Thompson2001) and judge their own immoral behavior as less egregious than that of others (e.g., Valdesolo & DeSteno Reference Valdesolo and DeSteno2007). Thus, our views of ourselves are consistently bolstered by means of self-serving biases and self-enhancement throughout our everyday existence. SD does not require demands from OD to have evolved – it is self-sustaining, and certainly provides considerable adaptive advantages independently. Although a capacity for SD may enhance one's skills in OD, it seems more likely that OD enjoys a commensal relationship with SD than that it drives the evolution of SD.