Free How We Know What Isn't So by Thomas Gilovich

outcomes occur frequently enough, they become part of our experiential background and go unnoticed. Departures from normality, in contrast, can generate surprise and draw attention. The unexpected can sometimes be unusually memorable.
    Consider cases of cancer remission. Sadly, people who are diagnosed as having certain forms of cancer rarely recover. An instance in which someone does recover, therefore, is rather noteworthy, particularly if the person did anything unconventional to try to effect a cure (such as visiting a faith healer or travelling to Mexico for Laetrile therapy). Because we do not expect people to get better, we hardly notice any time someone tries an uncoventional treatment and it fails; when such treatments are successful, in contrast, the outcome violates our expectations and stands out in our memory.
    Similarly, people’s beliefs in certain “jinxes” are partly due to the vividness of outcomes that depart from the base rate. People will often say things such as, “I hope I don’t jinx him, but Fred has never picked a losing stock.” It is easy to see how a concern about jinxing someone might arise. If a person has experienced such a large number of positive outcomes that it is worthy of comment, an additional success is not, by itself, terribly noteworthy. A subsequent failure, on the other hand, violates the typical pattern of success and thus stands out in the person’s experience. Examples of earlier jinxes are therefore easy to recall.
    One of the most interesting classes of events that depart from the baserate and thus stand out in everyday experience is what sociologist Erving Goffman referred to as “negatively eventful actions,” or those actions and customs that are so common and automatic that we only become aware of them when someone fails to honor them. 24 All of us have a preferred distance that we like to maintain from others—a “personal space” that governs the physical closeness of our interactions. Few of us, however, are aware of the precise dimensions or even the existence of such a bubble until someone invades it. It is only when someone violates the spacing norm that we even notice that it exists. Similarly, we tend to face forward in an elevator, pass fellow pedestrians on the right, and talk to people of different status with different styles of speech. All of this occurs with minimal awareness until we encounter someone who fails to uphold the norms.
    Goffman’s negatively eventful actions are perfect examples of one-sided events: The outcome is perceived as an event only when it comes out one way. Although the “expectations” in Goffman’s examples are generally vague and unarticulated, it is the dis confirmations that tend to stand out. Interestingly, these kinds of dis confirmations tend not to undermine a person’s pre-existing beliefs. A norm violation of the type Goffman describes certainly does not diminish one’s expectations about how people will behave in the future. If anything, it strengthens those expectations by making them more explicit.
    These asymmetries of pattern, hedonic consequences, etc., as well as one-sided events more generally, all serve to distort the evidential record that a person consults to evaluate the validity of various beliefs. For the most part, these asymmetries tend to accentuate information that is consistent with a person’s expectations and pre-existing beliefs. As a result, people tend to see in a body of evidence what they expect to see. What people expect to see, furthermore, is often what they want to see, and so the biasing effect of their preconceptions is often exacerbated by the biasing effect of their preferences and motives. This latter effect serves as the subject of the next chapter.
    * A blind observer is a person who is unaware of either the hypothesis under investigation or the specific condition of the experiment that is being run at any given time (e.g., treatment or control group). Because the