Blogs » Neurognosis » Perceptual Bias, Health Risks and Monkey Spheres


The “it can’t happen to me” phenomenon is often something we experience as well as seeing it in others. We seem to downplay risks involving ourselves in many respects and not simply in just health areas. However, for whatever reason this process seemed to come about, it often serves as a barrier to the acknowledgement of health risks and whether or not particular risks are personally salient. For example, Greening and Chandler (2006) performed a study examining people’s assessment of their risk in a vehicle accident both where they were the driver and were not. The authors found that people tended to overestimate their skill and abilities in such a situation when they were in control. When they were not in control, their perception of risk in an accident was much larger than when they were in control. This experiment and many others show we seem to view ourselves and our abilities as being “better” than others – a definite cognitive bias.

Perceptual bias in regard to ourselves does not seem limited to just our perceived risk in various situations. An example of this was found by Epley and Whitchurch (2008). As was found in Greening and Chandler’s (2006) study, Epley and Whitchurch also found that, “people’s inferences about their own traits are often enhancing” (p. 1159). The authors utilized a face recognition task in which the participants would attempt to recognize their own face in a line-up of morphed versions of their photo. Their responses to the photos were then gauged against their measured self-worth. They found that the participants were more likely to rate the more attractive morphs as their actual photos. The results indicated that most of the participants indicated that the 20% more attractive morph to be their actual photo. These results also seemed to be related to a person’s perception of self-esteem as well. In subsequent experiments in which the participants were asked to find their faces, a friend’s face and those of an experimenter’s, the participants again showed a self-enhancement bias but also showed similar bias for their friends. The results on the image task were also related to measures of self-esteem.

Weinstein (2003) shows that context is important in risk perception assessments. As the author states:

“A man who says that his risk of heart disease is ‘a little above average’ is giving a somewhat pessimistic risk rating, but if he smokes heavily, even this rating may be unrealistically optimistic. In contrast, a non-smoker with low cholesterol levels, normal blood pressure, and no family history of heart disease may be accurate in claiming that his risk is much below average” (p. 24).

People seem to rate themselves, on average, at a lower risk for health problems and many other situations which is independent of race, age, educational background, and occupation (Weinstein, 2003). This type of “universal” result may indicate a particular bias which has been with humanity for a very long time. Also, the bias’ connection to control would also allude to it being a self-centered or some type of self-preservation process. However, as was evidenced by Epley and Whitchurch (2008), similar results are found for friends as opposed to strangers. This may also suggest a process which holds a social group connection. The anthropologist Robin Dunbar made an interesting discovery in the 1990s in regard to social primate cognition. Dunbar (1992, 1993) proposed that the number of others that we can keep stable relationships with is limited. Utilizing observations from other great apes (chimpanzees and gorillas) and humans, Dunbar calculated that, for humans, this number is approximately 150. Outside of this 150, we tend not to view people as we do those who fall into this group which has been affectionately termed the “monkey sphere”. Such an idea seems to match well with the findings of Epley and Whitchurch as well as alluding to a long evolutionary history of this trait we call self-enhancement.

There is also evidence that this process is effective only in the short term. A study done by Robins and Beer (2001) found that self-enhancement, while it was beneficial in the short-term, may not be adaptive in a longer term. Their study specifically studied college students and beliefs about their academic ability compared to their actual performance and how their actual performance compared to their personal beliefs about their own ability. It was found that self-enhancement did not predict their academic performance nor graduation rates although it was correlated with narcissism, self-serving attributions, ego involvement as well as positive affect. This would seem to indicate that self-enhancement is not truly a reflection of ability or even a slight distortion thereof in that the authors seemed to find no real relationship between self-enhancement and performance academically. Immediacy is something which seems to pop up prevalently in regard to psychological processes of a more basic or primal nature – one which appeared earlier in our evolutionary history as social primates.

Is this process something which was directly selected for in our evolutionary history or is it simply a by-product of our evolution? With such cognitive processes such as self-enhancement, it may be impossible to tell and our experimentation may be limited to our best guesses and observation of other primates (Evans and Zarate, 1999). However, the question still remains. There are some aspects which may seem to allude to an evolutionary connection in social networks but as Gould and Lewontin (1979) proposed, this process may simply be an evolutionary spandrel. Gould and Lewontin rejected the idea that every aspect of an organism was shaped by natural selection directly; this was the adaptionist program they felt compelled to revise with a seminal paper published in 1979. They compared evolutionary by-products to the architectural spandrels in St. Mark’s cathedral in Venice in that biological spandrels appeared as a by-product or side-effect of a naturally selected adaptation. However, this is not to say that spandrels may not find themselves objects of selection either. Noam Chomsky viewed innate language structures arising as spandrels which eventually became the basis for our complex languages (Chomsky, 1972).

All this seems to beg the question, is this “normal”? From the previously mentioned studies and others as well, it would seem that it is quite prevalent in people. Hymes and Akiyama (1991) found that such self-enhancement may be, in fact, “normal”. The authors showed that the idea that depression has a negative correlation to self-enhancement holds across cultures in their study of Japansese and American students. In both samples, there was a definitive negative correlation between self-enhancement and depression. This would seem to imply that in a state such as depression which involves changes in self-appraisal, that the “normal” process of self-enhancement is impaired as well. This is evident not only in American populations but Japanese as well showing that there it is possibly a trend that transcends culture and race and may be more substantiation for a process arising long ago in our evolutionary history.

While the origin of our tendency to engage in self-enhancement may have arisen long ago in our primate ancestors or even more recently in our closer hominid ancestors, this trait seems to have created some problems for us in the present. As Weinstein (2003) and many other authors in different areas such as contraceptive use, medication adherence and et cetera have found, how self-enhancement effects our perception of risk may impact our decisions to engage in healthy behaviors. As is the nature of evolution in that traits which may have benefited our ancestors at one time may become a detriment to us, their descendants, self-enhancement may have arisen as a short-term “fix” of some sort but now impacts our need to recognize our vulnerability in respect to our health (Renner & Schwarzer, 2003). Effective health programs and theories may have a hard time piercing this barrier and it should be a large consideration in health education and recognition of health risks for all people.


Chomsky, Noam (1972). Language and mind. New York: Harcourt.

Dunbar, R. (1992). Neocortex size as a constraint on group size in primates. Journal of Human Evolution, 22, 469-493.

Dunbar, R. (1993). Coevolution of neocortical size, group size and language in humans. Behavioral and Brain Sciences, 16, 681-735.

Evans, D. & Zarate, O. (1999). Introducing evolutionary psychology. Cambridge, United Kingdom: Icon Books.

Greening, L. & Chandler, C. (2006). Why it can’t happen to me: The base rate matters, but overestimating skill leads to underestimating risk. Journal of Applied Social Psychology, 27, 760-780.

Hymes, R. & Akiyama, M. (1991). Depression and self-enhancement among Japanese and American students. Journal of Social Psychology, 131, 321-334.

Renner, B. & Schwarzer, R. (2003). Social-cognitive factors in health behavior change. In J. Suls & K. Wallston (Eds.). Social psychological foundations of health and illness. Malden: Blackwell Publishers.

Robins, R. & Beer, J. (2001). Positive illusions about the self: Short-term benefits and long-term costs. Journal of Personality and Social Psychology, 80, 340-352.

Weinstein, N. (2003). Exploring the links between risks perceptions and preventative health behavior. In J. Suls & K. Wallston (Eds.). Social psychological foundations of health and illness. Malden: Blackwell Publishers.