Keith Stanovich - How to Think Straight About Psychology

Folk beliefs are not always immune to evidence. Sometimes, when the contradictory evidence becomes too widely known, folk psychology (“common sense”) does change. For example, years ago, one widely held cliché about children was “Early ripe, early rot” (Fancher, 1985, p. 141). The cliché reflected the belief that childhood precocity was associated with adult abnormality, a belief sustained by many anecdotes about childhood prodigies who came to ruin in later life. In this case, the psychological evidence documenting the inaccuracy of the cliché has been absorbed into the general culture, and you will almost never hear this bit of folk “wisdom” anymore.

This last example also carries a warning by reminding us to beware of today’s “common sense”—because it is not difficult to show that yesterday’s common sense has often turned into today’s nonsense. After all, common sense is what “everybody knows,” right? Right. Well, everybody knows that women shouldn’t be able to vote, right? Everybody knows that African Americans shouldn’t be taught to read, right? Everybody knows that individuals with disabilities should be institutionalized out of the sight of society, right? In fact, 150 years ago, all of these beliefs were what “everybody knew.” Of course, we now recognize this common sense of the past as nonsense—as beliefs based on totally unverified assumptions. But in these examples we can see the critical role that psychology plays vis-à-vis common sense. Psychology tests the empirical basis of the assumptions of common sense. Sometimes the assumptions do not hold up when tested, as we saw in many of the previous examples. From the examples discussed—and many more could be cited—we can see that psychology’s role as the empirical tester of much folk wisdom often brings it into conflict with many widely held cultural beliefs. Psychology is often the bearer of the “bad tidings” that comfortable folk beliefs do not stand up to the cold light of day. Perhaps it is not surprising that many people would like not only to ignore the message but also to do away with the messenger.

There has always been opposition to an empirically based psychology. Just a little more than 100 years ago, Cambridge University refused to establish a psychophysics laboratory because the study of such a topic would “insult religion by putting the human soul on a pair of scales” (Hearst, 1979, p. 7). Psychology’s battle to establish its problems as empirically solvable has only recently been won. But as the science progresses, psychologists will address more and more issues that are the subject of strongly held beliefs about human beings because many of these problems are empirically testable. Psychologists now study such highly charged topics as the development of moral reasoning, the psychology of romantic love, the nature of racial prejudice, the efficacy of prayer, and the psychological and social determinants of religious beliefs. Studies of childhood sexual activity have incited much controversy (Lilienfeld, 2010; Rind, 2008). Some people object to empirical investigation in these areas; yet there has been scientific progress in each one of them.

Past president of the APA Gerald Koocher (2006) boldly warned us about the nature of psychological research by titling one of his presidential columns “Psychological Science is not Politically Correct.” In the article, he discussed research on topics such as the causes of obesity, what determines political attitudes, the relation between religion and sexual behavior, and domestic violence. He pointed out that the research findings on each of these topics have proved controversial, but that “psychological science cannot be held to a standard of political correctness by social liberals or conservatives” (p. 5).

Psychology is often in a no-win situation as a discipline. On one hand, some people object to calling psychology a science and deny that psychologists can establish empirical facts about behavior. On the other hand, there are those who object to the investigation of certain areas of human behavior because they fear that facts uncovered by psychology might threaten their beliefs. Skinnerian psychologists regularly deal with these contradictory criticisms. For instance, critics have argued that the laws of reinforcement formulated by behaviorists do not apply to human behavior. At the same time, other critics are concerned that the laws will be used for the rigid and inhumane control of people. Thus, the behaviorists are faced with some critics who deny that their laws can be applied and others who charge that their laws can be applied too easily!

Examples such as this arise because the relatively new science of psychology has just begun to uncover facts about aspects of behavior that have previously escaped study. The relative youth of psychology as a science partially explains why many people are confused about the discipline. Nevertheless, during the past several decades, psychology has become firmly established in the interconnecting structure of knowledge that we call science. Failure to appreciate this fact is the source of almost all of the confused thinking about psychology that you will encounter.

Psychology is an immensely diverse discipline covering a range of subjects that are not always tied together by common concepts. Instead, what unifies the discipline is that it uses scientific methods to understand behavior. The scientific method is not a strict set of rules; instead it is defined by some very general principles. Three of the most important are that (1) science employs methods of systematic empiricism; (2) it aims for knowledge that is publicly verifiable; and (3) it seeks problems that are empirically solvable and that yield testable theories (the subject of the next chapter). The structured and controlled observations that define systematic empiricism are the subject of several later chapters of this book. Science renders knowledge public by procedures such as peer review and mechanisms such as replication.

Psychology is a young science and, thus, is often in conflict with so-called folk wisdom. This conflict is typical of all new sciences, but understanding it helps to explain some of the hostility directed toward psychology as a discipline. This characteristic of questioning common wisdom also makes psychology an exciting field. Many people are drawn to the discipline because it holds out the possibility of actually testing “common sense” that has been accepted without question for centuries.

In 1793, a severe epidemic of yellow fever struck Philadelphia. One of the leading doctors in the city at the time was Benjamin Rush, a signer of the Declaration of Independence. During the outbreak, Rush was one of the few physicians who were available to treat literally thousands of yellow fever cases. Rush adhered to a theory of medicine that dictated that illnesses accompanied by fever should be treated by vigorous bloodletting (the removal of blood from the body either by using an instrument such as a lancet or by the application of leeches). He administered this treatment to many patients, including himself when he came down with the illness. Critics charged that his treatments were more dangerous than the disease. However, following the epidemic, Rush became even more confident of the effectiveness of his treatment, even though many of his patients had died. Why?

One writer summarized Rush’s attitude this way: “Convinced of the correctness of his theory of medicine and lacking a means for the systematic study of treatment outcome, he attributed each new instance of improvement to the efficacy of his treatment and each new death that occurred despite it to the severity of the disease” (Eisenberg, 1977, p. 1106). In other words, if the patient got better, this improvement was taken as proof that bloodletting worked. If instead the patient died, Rush interpreted this to mean that the patient had been too ill for any treatment to work. We now know that Rush’s critics were right: His treatments were as dangerous as the disease. In this chapter, we will discuss how Rush went wrong. His error illustrates one of the most important principles of scientific thinking, one that is particularly useful in evaluating psychological claims.