While the idea that being wrong can be strategically advantageous in the context of social strategy is sound, the idea that there is a “self” to be deceived might not be. The modular view of the mind finesses this difficulty and is useful – perhaps necessary – for discussing the phenomena currently grouped under the term “self-deception.”

Having evolved to escape detection of deception completely, self-deception must respond to social conditions registering different probabilities of detection. To be adaptive, it must have a mechanism to keep truthful information temporarily from the self during deception and retrieve it after deception. The memory system may serve this mechanism and provides a paradigm in which to conduct research on self-deception.

Von Hippel & Trivers (VH&T) propose that self-deception has evolved to facilitate the deception of others. However, they ignore the subjective moral costs of deception and the crucial issue of credibility in self-deceptive speech. A self-signaling interpretation can account for the ritualistic quality of some self-deceptive affirmations and for the often-noted gap between what self-deceivers say and what they truly believe.

By systematically biasing our beliefs, self-deception can endanger our ability to successfully convey our messages. It can also lead lies to degenerate into more severe damages in relationships. Accordingly, I suggest that the biases reviewed in the target article do not aim at self-deception but instead are the by-products of several other mechanisms: our natural tendency to self-enhance, the confirmation bias inherent in reasoning, and the lack of access to our unconscious minds.

Self-deception is a powerful but overapplied theory. It is adaptive only when a deception-detecting audience is in the loop, not when an inaccurate representation is invoked as an internal motivator. First, an inaccurate representation cannot be equated with self-deception, which entails two representations, one inaccurate and the other accurate. Second, any motivational advantages are best achieved with an adjustment to the decision rule on when to act, not with a systematic error in an internal representation.

Social desirability can be conceived as a proxy for self-deception, as it involves a positive attribution side and a denial side. People with mental disorders have lower scores on measures of social desirability, which could depend on cognitive load caused by symptoms. This suggests that self-deception is an active strategy and not merely a faulty cognitive process.

Deflationists about self-deception understand self-deception as the outcome of biased information processing, but in doing so, they lose the normative distinction between self-deception and wishful thinking. Von Hippel & Trivers (VH&T) advocate a deflationist approach, but they also want preserve the purposive character of self-deception. A biologically realistic analysis of deception can eliminate the contradiction implicit in their position.

Humans are not the only animals to deceive, though we might be the only ones that lie. The arms race von Hippel & Trivers (VH&T) propose may have only started during hominin evolution. VH&T offer a powerful theory, and I suggest it can be expanded to explain why there are systematic biases in human foresight.

Patients with physical symptoms for which no organic cause can be found are distributed along a continuum of disease simulation that ranges from a sincere belief of having a serious disease to intentional presentation of false symptoms. The evolutionary hypothesis that self-deception improves the deception of others can explain such a combination of unconscious and intentional production of physical symptoms.

Von Hippel & Trivers (VH&T) argue that people become effective liars through self-deception. It can be said, however, that people who believe their own stories are not lying. VH&T also argue that people are quite good lie detectors, but they provide no evidence for this, and the available literature contradicts their claim. Their reasons to negate this evidence are unconvincing.

Commentators raised 10 major questions with regard to self-deception: Are dual representations necessary? Does self-deception serve intrapersonal goals? What forces shape self-deception? Are there cultural differences in self-deception? What is the self? Does self-deception have costs? How well do people detect deception? Are self-deceivers lying? Do cognitive processes account for seemingly motivational ones? And how is mental illness tied up with self-deception? We address these questions and conclude that none of them compel major modifications to our theory of self-deception, although many commentators provided helpful suggestions and observations.