In our review of some of the many cognitive biases that affect our social judgment, we have seen that the effects on us as individuals range from fairly trivial decisions; for example, which phone to buy (which perhaps doesn’t seem so trivial at the time) to potentially life and death decisions (about methods of travel, for instance).
However, when we consider that many of these errors will not only affect us but also everyone around us, then their consequences can really add up. Why would so many people continue to buy lottery tickets or to gamble their money in casinos when the likelihood of them ever winning is so low? One possibility, of course, is the representative heuristic—people ignore the low base rates of winning and focus their attention on the salient likelihood of winning a huge prize. And the belief in astrology, which all scientific evidence suggests is not accurate, is probably driven in part by the salience of the occasions when the predictions do occur—when a horoscope is correct (which it will of course sometimes be), the correct prediction is highly salient and may allow people to maintain the (overall false) belief as they recollect confirming evidence more readily.
People may also take more care to prepare for unlikely events than for more likely ones because the unlikely ones are more salient or accessible. For instance, people may think that they are more likely to die from a terrorist attack or as the result of a homicide than they are from diabetes, stroke, or tuberculosis. But the odds are much greater of dying from the health problems than from terrorism or homicide. Because people don’t accurately calibrate their behaviors to match the true potential risks, the individual and societal costs are quite large (Slovic, 2000).
As well as influencing our judgments relating to ourselves, salience and accessibility also color how we perceive our social worlds, which may have a big influence on our behavior. For instance, people who watch a lot of violent television shows also tend to view the world as more dangerous in comparison to those who watch less violent TV (Doob & Macdonald, 1979). This follows from the idea that our judgments are based on the accessibility of relevant constructs. We also overestimate our contribution to joint projects (Ross & Sicoly, 1979), perhaps in part because our own contributions are so obvious and salient, whereas the contributions of others are much less so. And the use of cognitive heuristics can even affect our views about global warming. Joireman, Barnes, Truelove, and Duell (2010) found that people were more likely to believe in the existence of global warming when they were asked about it on hotter rather than colder days and when they had first been primed with words relating to heat. Thus the principles of salience and accessibility, because they are such an important part of our social judgments, can create a series of biases that can make a difference on a truly global level.
As we have already seen specifically in relation to overconfidence, research has found that even people who should know better—and who need to know better—are subject to cognitive biases in general. Economists, stock traders, managers, lawyers, and even doctors have been found to make the same kinds of mistakes in their professional activities that people make in their everyday lives (Byrne & McEleney, 2000; Gilovich, Griffin, & Kahneman, 2002; Hilton, 2001). And the use of cognitive heuristics is increased when people are under time pressure (Kruglanski & Freund, 1983) or when they feel threatened (Kassam, Koslov, & Mendes, 2009), exactly the situations that often occur when professionals are required to make their decisions.