A misbelief is simply a false belief, or at least a belief that is not correct in all particulars. We can see this metaphorically: If truth is a kind of target that we launch our beliefs at, then misbeliefs are to some extent wide of the mark. Of course, there is no philosophical consensus about just what a belief actually is. In most of what follows we intend to avoid this question, but we offer here the following working definition of belief, hopefully general enough to cover most representationalist and dispositional accounts: A belief is a functional state of an organism that represents that organism’s endorsement of a particular state of affairs as actual. A misbelief, then, is a belief that to some degree departs from actuality, i.e. it is a functional state endorsing a particular state of affairs that happens not to maintain.

A prevailing assumption is that those beliefs which maximise survival will be those which best approximate reality (D. C. Dennett 1987, Millikan 1984a, 1984b, 1993). Humans are thus assumed to have been biologically engineered to form true beliefs – by evolution. The notion that true beliefs are adaptive is excellently summarized by M. Scott Peck, author of The Road Less Traveled:

The more clearly we see the reality of the world, the better equipped we are to deal with the world. The less clearly we see the reality of the world – the more our minds are befuddled by falsehood, misperceptions and illusions – the less able we will be to determine correct courses of action and make wise decisions. Our view of reality is like a map with which to negotiate the terrain of life. If the map is true and accurate, we will generally know where we are, and if we have decided where we want to go, we will generally know how to get there. If the map is false and inaccurate, we generally will be lost (1978, p. 44).

Peck’s book, of course, is a work of pop psychology rather than cognitive science, and as such is more concerned with what is “psychologically adaptive” rather than evolutionarily adaptive. Nevertheless, his “map” analogy resonates with the earlier view of Ramsey that beliefs are “maps by which we steer” (1931, p. 238). According to Paglieri (2006), this is a view shared by most contemporary philosophers interested in practical reasoning, although others have emphasised that talk of beliefs as maps and true beliefs as accurate maps is just metaphorical: “I believe that… Interstate 5 runs from Solana Beach to La Jolla, but there is nothing in my brain that… has the shape of the southern California freeway system” (Stich 1990, p. 102).

In any case, it remains a widely held assumption that organisms that operate with accurate notions about how the world is structured, about how it works, are better suited to navigating the world and to satisfying their needs for survival. Shifting metaphorical gears, our beliefs about the world (about what is or isn’t true) are essentially tools that enable us to act effectively in the world. So beliefs are tools, and true beliefs, it is assumed, are effective tools. A corollary of this assumption is that we tend to adopt an alethic construal of proper-belief-formation-system-functioning – we consider belief-formation systems to be functioning properly when belief-formation is predicated upon truth-aiming, alethic reasons (Mele 1993, Millikan 1993).

If, however, evolution has designed us to accurately appraise the world and to form true beliefs, how are we to account for the routine exceptions to this rule - instances of misbelief? After all, no-one can deny that our beliefs do often miss the mark, alethically speaking. Most of us believe propositions that end up being disproven, many of us produce beliefs that others consider obviously false to begin with, and some of us form beliefs that are not just manifestly but bizarrely false. How can this be? The prevailing answer to this question is that misbeliefs result from glitches or breakdowns in the machinery of belief formation. If we conceive of the belief formation system as an information processing system that takes certain inputs (e.g. perceptual inputs) and (via manipulations of these inputs) produces certain outputs (beliefs), then misbeliefs arise from dysfunction in the system. Such misbeliefs are the faulty output of a disordered, defective, abnormal cognitive system.

The fact that we are not presently equipped with fail-safe belief-formation systems does not tell against an evolutionary perspective, any more than do the facts that we are not currently endowed with light-speed nervous systems (Stich 1990) or infallible visual systems. This is because evolution does not necessarily produce optimally designed systems (Dawkins 1982, Stich 1990) and in fact often conspicuously fails to do so. It would be panglossian to think otherwise (Gould & Lewontin 1979, Voltaire 1759/1962):

“Brilliant as the design of the eye is, it betrays its origin with a tell-tale flaw: the retina is inside out… No intelligent designer would put such a clumsy arrangement in a camcorder” (D. C. Dennett 2005, p. 11).

Evolutionary explorations in Design Space are constrained, among other things, by economic considerations (beyond a certain level, system improvements may exhibit declining marginal utility; Stich 1990), historical vicissitude (the appropriate mutations must occur if selection is to act on them) and the topography of the fitness landscape (selection cannot access optimal design solutions if it must traverse a fitness valley to do so; D. C. Dennett 1995). Evolution, in short, is an imperfect design process, and the products of that process (like the products of other imperfect designers) are imperfect; sometimes the mechanisms miss their target (truth) because of their imperfections.

Our intention in this paper is to offer a gloss on the prevailing evolutionary view of misbelief that corrects some important oversimplifications. We agree that misbeliefs can indeed result from imperfections in the belief formation system. We argue, however, that not all misbeliefs arise that way – specifically, there are certain situations in which misbelief can actually be adaptive. In those situations, therefore, we can expect that we will be evolutionarily predisposed to form misbeliefs. In short, misbelief evolves.

Note that what we are claiming here is not merely that misbeliefs can occasionally arise in the normal course of the belief formation system’s operations. After all, just as there are normal (non-defective) readers who misread words on occasion, so there are normal belief-formation systems that produce misbeliefs on occasion; moreover, in some circumstances, these systems may produce misbeliefs even while functioning normally. Millikan articulates this possibility:

[T]hat John has a false belief need not indicate that his belief-manufacturing mechanisms are faulty. Indeed, it need not indicate that anything in him is abNormal (except the belief). Perhaps his belief-making mechanisms have been laboring under external conditions not Normal for performance of their proper functions… Similarly, when John perceives things wrongly this is not always the fault of his perceptual systems. Sometimes Normal conditions for proper functioning of these systems are not met, as when the train on the track next to the Latvian express leaves the station but John’s perception is that it is his train that is leaving instead… Because our belief-making systems are dependent for their proper operation upon numerous conditions for which the body’s systems are not responsible, it is not surprising if many of the beliefs of perfectly healthy people are false (Millikan 1993, p.74, italics in original).

The fact that our belief-formation systems depend for their proper operation upon certain external conditions is a limitation of those systems, but not a defect. Because evolution is an imperfect design process, the systems we have evolved for representing reality are bound to be limited. However, other things being equal, we might expect that our belief-formation systems would be designed to minimise the occurrence of errors – to minimise misbelief. If true beliefs are adaptive (Millikan 1993), then surely it is adaptive to maximise their number? In the next section we will show that this assumption is false – in certain cases it is adaptive to have more rather than less misbeliefs.

Error Management Theory:

We note that it is easy to dream up anomalous offbeat scenarios where true beliefs are in fact detrimental for survival:

[Harry] believed that his flight left at 7:45am… Harry’s belief was true, and he got to the airport just on time. Unfortunately, the flight crashed, and Harry died. Had Harry falsely believed that the flight left at 8:45, he would have missed the flight and survived. So true belief is sometimes less conducive to survival than false belief (Stich 1990, p. 123).

As Stich (1990) notes, cases such as this are highly unusual, and do little to obviate the claim that true beliefs are generally adaptive (see also Millikan 1993). After all, natural selection does not act on anomalous particulars, but rather upon reliable generalizations. Our question, then, is whether there might be cases where misbelief is systematically adaptive.

In many circumstances, perhaps most (but not all, as we shall claim), the ideal belief-formation system would be one that formed completely accurate beliefs 100% of the time (Haselton & Buss 2000, Stich 1990). Given that such a system is virtually impossible, however (Stich 1990), trade-offs may arise between overall doxastic accuracy and accuracy in certain situations. Dennett illustrates this point:

[I]t might be better for beast B to have some false beliefs about whom B can beat up and whom B can’t. Ranking B’s likely antagonists from ferocious to pushover, we certainly want B to believe it can’t beat up all the ferocious ones and can beat up all the obvious pushovers, but it is better (because it “costs less” in discrimination tasks and protects against random perturbations such as bad days and lucky blows) for B to extend “I can’t beat up x” to cover even some beasts it can in fact beat up. Erring on the side of prudence is a well-recognized good strategy, and so Nature can be expected to have valued it on occasions when it came up (D. C. Dennett 1987, p. 51, fn. 3).

Stich echoes the logic of this scenario with an example of his own:

Consider, for example, the question of whether a certain type of food is poisonous. For an omnivore living in a gastronomically heterogeneous environment, a false positive on such a question would be relatively cheap. If the organism comes to believe that something is poisonous when it is not, it will avoid that food unnecessarily. This may have a small negative impact on its chances of survival and successful reproduction. False negatives, on the other hand, are much more costly in such situations. If the organism comes to believe that a given kind of food is not poisonous when it is, it will not avoid the food and will run a substantial risk of illness or death (1990, pp. 61-62).

What these examples suggest is that when there are reliable “asymmetries in the costs of errors” (Bratman 1992), i.e. when one type of error (false positive or false negative) is consistently more detrimental to fitness than the other, then a system that is biased toward committing the less costly error may be more adaptive than an unbiased system.[1] The suggestion that biologically engineered systems of decision and belief formation exploit such adaptations is the basis of Error Management Theory (EMT; Haselton forthcoming, Haselton & Buss 2000, 2003, Haselton & Nettle 2006). According to EMT, cognitive errors (including misbeliefs) are not necessarily malfunctions reflecting limitations of evolutionary design; rather, such errors may reflect judicious systematic biases that maximise fitness despite increasing overall error rates.

Haselton and Buss (2000) use EMT to explain the established phenomenon whereby men overperceive the sexual interest and intent of women (e.g. Abbey 1982, Haselton 2003). They argue that, for men, the perception of sexual intent in women is a domain characterised by recurrent cost asymmetries, such that the cost of inferring sexual intent where none exists (a false-positive error) is outweighed by the cost of falsely inferring a lack of sexual intent (a false-negative). The former error may cost some time and effort spent in fruitless courtship, but the latter error will entail a missed sexual and thus reproductive opportunity – an altogether more serious outcome as far as fitness is concerned.

For women, the pattern of cost asymmetries is basically reversed. The cost of inferring a man’s interest in familial investment where none exists (a false-positive error) would tend to outweigh the cost of falsely inferring a lack of such interest (a false-negative). The former error may entail the woman consenting to sex and being subsequently abandoned, a serious outcome indeed in arduous ancestral environments. The latter error, on the other hand, would tend merely to delay reproduction for the woman – a less costly error, especially given that reproductive opportunities are generally easier for women to acquire than men (Haselton forthcoming). EMT thus predicts that women will tend to underperceive men’s intention to commit, a prediction that has received empirical support (Haselton forthcoming, Haselton & Buss 2000).

Other EMT predictions that have received empirical support include the hypotheses that recurrent cost asymmetries have produced evolved biases toward overinferring aggressive intentions in others (Duntley & Buss 1998, Haselton & Buss 2000), particularly members of other racial and ethnic groups (Haselton & Nettle 2006, Quillian & Pager 2001); toward overinferring potential danger with regard to snakes (see Haselton & Buss 2003, Haselton & Nettle 2006); toward underestimating the arrival time of approaching sound sources (Haselton & Nettle 2006, Neuhoff 2001); and - reflecting Stich’s (1990) example above – toward overestimating the likelihood that food is contaminated (see Rozin & Fallon 1987, Rozin, Markwith, & Ross 1990).

One objection that might be raised at this point is that the above examples need not actually involve misbelief. Stich’s omnivore need not believe that the food in question is poisonous – it need not believe anything one way or the other about the food. The issue here is the issue of what doxastic inferences we can draw from the animal’s behaviour. Most commentators would agree that prudent action should not be confused with belief. After all, we always look before crossing a road, even where we are almost positive that there is no oncoming traffic. Our actions in such a case should not be read as reflecting a belief that there is an oncoming vehicle, but rather as reflecting a belief that there might be an oncoming vehicle (and the absence of a vehicle will not render false the latter belief). If we had to bet our lives one way or another on the matter, we might well bet that there isn’t an oncoming vehicle (Bratman 1992). Betting one’s life one way or the other, however, is a paradigm case of error symmetry (if we’re wrong, we die – no matter which option we choose). In everyday cases of crossing the road, however, the errors are radically asymmetrical – an error one way may indeed mean serious injury or death, but an error the other way will mean only that we have wasted the energy required to turn our heads a couple of times.

The upshot of this criticism is that tendencies to “overestimate” the likelihood that food is contaminated, to “overperceive” the sexual interest of women, or to “overinfer” aggressive intentions in others, may reflect judicious decision criteria for action rather than misbeliefs. In other terminology, such tendencies may reveal not (mis)beliefs, but merely acceptances:

To accept a proposition is to treat it as a true proposition in one way or another […] to act, in certain respects, as if one believed it (Stalnaker 1984, pp. 79-80).

Nature may well prefer to err on the side of prudence, but does she need to instil erroneous beliefs to accomplish this? Or can she make do with cautious acceptances? We move on now to a consideration of evolutionarily adaptive cases where it seems necessary to invoke actual, bona fide (mis)beliefs.

Positive Illusions:

The perception of reality is called mentally healthy when what the individual sees corresponds to what is actually there.

~ Jahoda (1958, p. 6)

In parallel with the prevailing evolutionary view of adaptive belief, a number of psychological traditions have regarded close contact with reality as a cornerstone of mental health (Gana, Alaphilippe, & Bailly 2004, Krebs & Denton 1997, Taylor & Brown 1988). A substantial body of research in recent decades, however, has challenged this view, suggesting instead that optimal mental health is associated with unrealistically positive self-appraisals and beliefs. Taylor and colleagues (e.g. Taylor 1989, Taylor & Brown 1988) refer to such biased perceptions as positive illusions. Given that positive illusions are defined as beliefs that depart from reality (Taylor & Brown 1988), they qualify as misbeliefs. Such illusions include unrealistically positive self-evaluations, exaggerated perceptions of personal control or mastery, and unrealistic optimism about the future.

For example, evidence indicates that there is a widespread tendency for most people to see themselves as better than others on a range of dimensions. This is the better-than-average effect (Alicke 1985) - individuals, on the average, judge themselves to be more intelligent, honest, persistent, original, friendly and reliable than the average person. Most college students tend to believe that they will have a longer-than-average lifespan, while most college instructors believe that they are better-than-average teachers (Cross 1977). Most people also tend to believe that their driving skills are better than average – even those who have been hospitalised for accidents (e.g. McKenna, Stanier, & Lewis 1991, Williams 2003). In fact, most people view themselves as better than average on almost any dimension that is both subjective and socially desirable (Myers 2002). Indeed, with exquisite irony, most people even see themselves as less prone to such self-serving distortions than others (Friedrich 1996, Pronin, Gilovich, & Ross 2004, Pronin, Lin, & Ross 2002).

Positive illusions may well be pervasive, but are they adaptive, evolutionarily speaking? For example, do such misbeliefs sustain and enhance physical health and fitness? Research into positive illusions has indicated that unrealistically positive views of one's medical condition and of one's ability to influence it are associated with increased health and longevity (Taylor, Lerner, Sherman, Sage, & McDowell 2003). For example, in studies with HIV-positive and AIDS patients, those with unrealistically positive views of their likely course of illness showed a slower illness course (Reed, Kemeny, Taylor, & Visscher 1999) and a longer survival time (Reed, Kemeny, Taylor, Wang, & Visscher 1994, for a review see Taylor, Kemeny, Reed, Bower, & Gruenewald 2000).

Taylor et al. (2000) conjectured that positive illusions might work their medical magic by regulating physiological and neuroendocrine responses to stressful circumstances. Stress-induced activation of the autonomic nervous system and the hypothalamic-pituitary-adrenocortical (HPA) axis facilitates “fight or flight” responses and is thus adaptive in the short-term. Chronic or recurrent activation of these systems, however, may be detrimental to health (see McEwen 1998), so psychological mechanisms that constrain the activation of such systems may be beneficial. Consistent with the above hypothesis, Taylor et al. (2003) found that self-enhancing cognitions in healthy adults were associated with lower cardiovascular responses to stress, more rapid cardiovascular recovery, and lower baseline cortisol levels.

Results linking positive illusions to health benefits are consistent with earlier findings that patients who deny the risks of imminent surgery suffer fewer medical complications and are discharged more quickly than other patients (Goleman, 1987, cited in Krebs & Denton 1997), and that women who cope with breast cancer by employing a denial strategy are more likely to remain recurrence-free than those utilising other coping strategies (Dean & Surtees 1989). In such cases the expectation of recovery appears to facilitate recovery itself, even if that expectation is unrealistic. This dynamic may be at work in cases of the ubiquitous placebo effect, whereby the administration of a medical intervention instigates recovery before the treatment could have had any direct effect and even when the intervention itself is completely bogus (Humphrey 2004).

What is striking about these phenomena of positive illusions, from the point of view of the theorist of beliefs as representations, is that they uncover the implicit holism in any system of belief-attribution. To whom do the relevant functional states represent the unrealistic assessment? If only to the autonomic nervous system and the HPA, then theorists would have no reason to call the states misbeliefs at all, since the more parsimonious interpretation would be an adaptive but localized tuning of the error management systems within the modules that control these functions. The fact that this apparently benign and adaptive effect has been achieved by the maintenance of a more global state of falsehood (as revealed in the subjects’ responses to questionnaires, etc.) is itself, probably, an instance of evolution’s sub-optimality as an engineer: in order to achieve this effect, evolution has to misinform the whole organism. With this model to guide us, we may discover similar free-floating rationales (D. C. Dennett 1995, Daniel C. Dennett 2006) for some of the bizarre religious beliefs (apparent misbeliefs) encountered by ethnographers and other social scientists.

Ryan McKay and Daniel Dennett

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