How to Think Straight About Psychology

Keith Stanovich (1989)


In the preceding chapter we suggested, but did not explicitly state, a fact of fundamental importance: psychology is a data-based scientific discipline. Understanding the implications of this fact is the single most important step that a layperson can take in developing the ability to think straight about psychology.

People outside the discipline commonly deny that psychology is a science. Some of these objections are put forth quite strongly and probably affect public opinion. Attempts to convince the public that psychology cannot be a science often stem from two sources. The first source includes many of the purveyors of bogus psychology, who have a vested interest in maintaining the public's attitude that anything goes in psychology, that there are no rational criteria for evaluating psychological claims. This is the perfect atmosphere in which to market such offers as "Lose weight through hypnosis," "Develop your hidden psychic powers," "Learn French while you sleep," and the many other parts of the multimillion-dollar self help industry that either are not based on scientific evidence or, in many cases, are actually contradicted by much available evidence.

Most people who claim that psychology is not a science derive no material benefit from their belief, however. The resistance from this second source simply reflects an understandable tendency to oppose the expansion of science into areas where unquestioned authorities and "common sense" have long reigned. History provides many examples of initial public resistance to the use of science rather than philosophical speculation, theological edict, or folk wisdom to explain the natural world. Each science has gone through a phase of resistance to its development. Hypatia of Alexandria, the last scholar to work in the great library there, was murdered by members of the early Christian church because her interest in science and leaming was associated with paganism. Learned contemporaries of Galileo refused to look into his new telescope because the existence of the moons of Jupiter would have violated their philosophical and theological beliefs. For centuries, the understanding of human anatomy progressed only haltingly because of lay and ecclesiastical prohibitions against the dissection of human cadavers. Charles Darwin was repeatedly denounced. Paul Broca's Society of Anthropology was opposed in France because knowledge about human beings was thought to be subversive to the state.

Each scientific step to greater knowledge about human beings has evoked opposition. This opposition eventually dissipated, however, when people came to realize that science does not defile humanity by its investigations but instead contributes to human fulfillment by widening the sphere of knowledge. Who now believes that astronomy's mapping of the galaxies and intricate theories about the composition of distant stars destroy our wonder at the universe? Who would substitute the health care available in their community for that available before human cadavers were routinely dissected? An empirical attitude toward the stars or the human body has not diminished humanity. More recently, Darwin's evolutionary synthesis has laid the foundation for startling advances in genetics and biology. Nevertheless, as we get closer to the nature of human beings and their origins, vestiges of opposition remain. In the United States, religious extremists continue to advocate the teaching of creationism in the public schools, and surveys show that the scientific fact that humans evolved from lower organisms is not accepted by a large portion (in some surveys, a majority) of the public. If evolutionary biology, with its long and impressive record of scientific achievements, can still engender public opposition, is it any wonder that psychology, the most recent discipline to bring long-held beliefs about human beings under scientific scrutiny, currently provokes people to deny its validity?

Before we can acknowledge that psychology is a science, we must understand what science is. Indeed, many who deny psychology the status of a science are themselves quite confused about the nature of science. Every undergraduate psychology instructor has encountered the beginning student who is majoring in psychology "because I don't like science." The instructor is, of course, prepared for the student's incredulity when informed that psychology is indeed a member of the sciences (I can't believe I have to take statistics!). When the instructor asks, "Have you taken much biology or chemistry since coming to the university?" the reply is very predictable: Oh no, I've always avoided science. The student knows nothing about the sciences but is absolutely certain that psychology is not one of them. Unfortunately, this attitude characterizes many of psychology's critics.


To answer the question, What is science? we can begin by dealing with what science is not. In this way, we can rid ourselves of the vast majority of common misconceptions. First, science is not defined by subject matter. Any aspect of the universe is fair game for the development of a scientific discipline. This includes all aspects of human beings, including their behavior and brain functions. We cannot divide the universe into "scientific" and "nonscientific" topics. Although strong forces throughout history have tried to place human beings outside of the sphere of scientific investigation, they have been unsuccessful, as you shall see. The reactions against psychology as a scientific discipline probably represent the modem remnants of this ancient struggle. A claim that human behavior cannot be studied scientifically-which would rule psychology out of the sciences by definition-should not be accepted as a given but should be viewed as a hypothesis that can be evaluated. In fact, this hypothesis has been evaluated. It is false.

Science is also not defined by the use of particular experimental apparatus. It is not the test tube, the computer, the electronic equipment, or the investigator's white coat that defines science. These are the trappings of science, but they are not its defining features. (If this were the case, there would be no question about psychology's status because psychology departments in all major universities are full of computers, chemicals, and electronic equipment Of all types.)

Finally, science is not defined by a specific method. Rather it is a way of thinking about and observing the universe that leads to a deep understanding of its workings. The principles governing science are general and broad in scope. They are not sequences of rigid rules.

In this chapter we will discuss three important and interrelated features that define science. They are (1) the use of systematic empiricism, (2) the production of public knowledge, and (3) the examination of solvable problems. Although we will examine each feature separately, remember that the three connect to form a coherent general structure. (For a more detailed discussion of the general characteristics of science, see the works of Bronowski, Popper, Cournaud, and Medawar in the references section of this book.)

Systematic Empiricism

If you look up the word empiricism in any dictionary, you will find that it means "the practice of relying on observation." Although this seems clear enough, there is an even simpler way of defining empiricism. The empirical attitude in science can be summarized by the phrase "Let's take a look." Scientists find out about the world by examining it. The fact that this may seem obvious to You is an indication of the spread of the scientific attitude in the last couple of centuries. In the past, it has not always seemed so obvious. Recall the refusal to look into Galileo's telescope. It was long thought that the way to know about the world was through pure thought and argument or appeal to authority. Galileo claimed to have seen moons around the planet Jupiter. Another astronomer, Francesco Sizi, attempted to refute Galileo, not with observations, but with the following argument:

There are seven windows in the head, two nostrils, two ears, two eyes and a mouth; so in the heavens there are two favorable stars, two unpropitious, two luminaries, and Mercury alone undecided and indifferent. From which and many other similar phenomena Of nature such as the seven metals, etc., which it were tedious to enumerate, we gather that the number of planets is necessarily seven.... Besides, the Jews and other ancient nations, as well as modern Europeans, have adopted the division of the week into seven days, and have named them from the seven planets: now if we increase the number of planets, this whole system falls to the ground.... Moreover, the satellites are invisible to the naked eye and therefore can have no influence on the earth and therefore would be useless and therefore do not exist. (Holton & Roller, 1958, p. 160)

The point is not that the argument is laughably idiotic, but that it was seen as a suitable rebuttal to an actual observation. We laugh now because we have the benefit of hindsight. Three centuries of the demonstrated power of the empirical approach give us an edge on poor Sizi. Take away those years of empiricism and many of us may have been there nodding our heads and urging him on. No, the empirical approach is not necessarily obvious, which is why we often have to teach it, even in a society that is dominated by science.

Empiricism pure and simple is not enough, however. Note that the heading for this section is systematic empiricism. Observation is fine and necessary. But pure, unstructured observation of the natural world will not lead to scientific knowledge. Write down every observation you make from the time you get up until the time you go to bed on a given day. When you finish, you will have a great number of facts, but you will not have a greater understanding of the world. Scientific observation is termed systematic because it is structured so that the results of the observation reveal something about the underlying nature of the world. Scientific observations are usually theory driven; they test different explanations of the nature of the world. They are structured so that, depending on the outcome of the observation, some theories are supported and others rejected..

We will see more specifically what systematic means in later chapters. Here, we want to emphasize that psychology has only recently become empirically based and that this has implications for public understanding of the discipline. Psychologist Donald Broadbent (1961) has discussed why the development of psychology means that we must make the transition from armchair speculation about behavior to an empirical orientation in the following:

There are therefore great dangers in any attempt to short-cut the study of behaviour. From all the labours of the past fifty years, three main lessons can perhaps be learned for everyday life: and the first of these is that an objective attitude to behavior is possible and essential if we are not to accept glib generalizations. When, for example, we are told that income-tax discourages the working of overtime in industry, our response should not be to ask ourselves if this is intuitively reasonable, but to see whether the records of an actual factory support the statement. When we put the knobs on a gas-stove we should not put them in the place which seems natural to us, but try out a number of arrangements on a large sample of people who might use the stove. In many of the cases in which we blandly make assumptions about human nature, it is possible to get evidence. (p. 202)

Publicly Verifiable Knowledge

Scientific knowledge is public in a special sense. By public, we do not mean that the results of scientific observations are posted on community center bulletin boards. Instead, we refer to the fact that scientific knowledge does not exist solely in the mind of a particular individual. In an important sense, scientific knowledge does not exist at all until it has been publicly submitted to the scientific community for criticism and empirical testing. Knowledge that is considered "special"-the province of the thought processes of a particular individual, immune from scrutiny and criticism by others-can never have the status of scientific knowledge.

Here is where the technical criterion of replication becomes important. In order to be considered in the realm of science, a finding must be presented to the scientific community in a way that enables other scientists to attempt the same experiment and obtain the same results. Scientists use replication to define the idea of public knowledge. It ensures that a particular finding is not due simply to the errors or biases of a particular investigator. In short, for a finding to be accepted by the scientific community, it must be possible for someone other than the original investigator to duplicate it. When a finding is presented in this way, it becomes public. It is no longer the sole possession of the original researcher but is instead available for other investigators to extend, criticize, or apply in their own ways.

John Donne, in his most famous sermon, told us that "no man is an island." In science, no researcher is an island. Each investigator is connected to the scientific community and its knowledge base because the knowledge can be communicated from scientist to scientist. It is this interconnection that enables science to grow cumulatively. Researchers constantly build on previous knowledge in order to go beyond what is currently known., This is possible only if previous knowledge is stated in such a way that any investigator can use it to build on.

By publicly verifiable knowledge, then, we mean findings presented to the scientific community in such a way that they can be replicated, criticized, or extended by anyone in the community. This is a most important criterion not only for scientists, but also for the layperson who, as a consumer, must evaluate scientific information presented in the media. As we will see in chapter 10, one important way to distinguish charlatans and practitioners of pseudoscience from legitimate scientists is that the former often bypass the normal channels of scientific publication and criticism and instead go straight to the media with their "findings." One ironclad criterion that will always work for the public when presented with scientific claims of uncertain validity is the question: Have the findings been published in a recognized scientific journal that employs some type of peer review procedure? The answer to this question will almost always separate pseudoscientific claims from the real thing.

Not all information in scientific journals is necessarily correct, but it has met a minimal criterion of peer criticism and scrutiny. Most scientific disciplines publish many different journals (although these journals often vary greatly in quality), so that most scientific ideas can get published somewhere in the legitimate literature if they meet some minimal standards. The idea that only a narrow range of data and theory can get published in science is false. This is particularly true in psychology where journals publish papers on an enormous variety of topics and from a wide variety of theoretical perspectives.

Table 2 lists the names of only a fraction of the journals from which articles are summarized in the publication Psychological Abstracts. Most of the journals listed in the table are peer reviewed. Peer review is a procedure in which each paper submitted to a journal is critiqued by several scientists who then submit their criticisms to an editor (usually a scientist with an extensive history of work in the specialty area covered by the journal) who decides whether the weight of opinion warrants publication of the paper, publication after further experimentation and statistical analysis, or rejection because the research is flawed or trivial. Most journals carry a statement of editorial policy in each issue, so it is easy to check whether a journal is peer reviewed.

The mechanisms of peer review vary somewhat from discipline to discipline, but the underlying rationale is the same. Peer review is one way (replication is another) that science institutionalizes the attitudes of objectivity and public criticism. Ideas and experimentation undergo a honing process in which they are submitted to other critical minds for evaluation. Ideas that survive this critical process have begun to meet the criterion of public verifiability. Not all ideas published in the journals summarized in Psychological Abstracts are necessarily good or correct, but failure to appear in an established scientific source is a good sign that a claim is unfalsifiable (a topic we will consider in chapter 3), not replicable, or simply wrong. Thus, the consumer of psychological research can rely on the general rule: if empirical support for a psychological claim has not appeared in the established, peer-reviewed journals of psychology, it is highly likely that the claim is bogus.

Solvable Problems

Science deals with solvable, or specifiable, problems. This means that the type of questions that scientists address are potentially answerable with currently available empirical techniques. If a problem is not solvable with the empirical techniques that scientists have at hand, then scientists will not attack it. For example, the question, "Will three-year-old children given structured language stimulation during day care be ready for reading instruction at an earlier age than children not given such extra stimulation?" represents a scientific problem. It is answerable by currently available empirical methods. The question, Are human beings inherently good or inherently evil? is not an empirical question and, thus, is simply not in the realm of science.

You should be aware of two important misunderstandings regarding this third characteristic of science. We have said that science deals only with a certain class of problem-the kind that is empirically solvable. This most definitely does not mean that scientists believe that questions in the realm of science are the only important questions. Unfortunately, nonscientists often make such an inference, though scientists rarely voice such opinions.

Scientists do focus on a certain class of problem, but there is no implied denigration of nonscientific problems in this natural division of labor. Scientists are not concerned that the expert on Thomas Hardy does not set aside a day once in a while to study messenger RNA. On the other hand, it is similarly wrong to infer that the solid-state physicist who does not devote time to the study of Alfred Lord Tennyson's Idylls of the King is denying the importance of literature and poetry. In short, just because scientists do not address nonscientific questions in their professional work, it does not follow that they are unconcerned about such questions. Informed artists are often concerned about current developments in science; so, too, scientists recognize the importance of philosophical debates and the artistic and literary developments that affect our culture.

By saying that scientists tackle solvable problems, we do not mean to imply that different classes of problems are inherently solvable or unsolvable and that this is fixed forever. Quite the contrary: Some problems that are unsolvable, given currently available empirical techniques, may become solvable as theory and empirical techniques become more sophisticated. This is how science in general has developed and how new sciences have come into existence. There is always ample room for disagreement about what is currently solvable. Scientists themselves often disagree on this point as it relates to current problems of ambiguous status. Thus, while all scientists agree on the solvability criterion, they may disagree on its specific applications. Peter Medawar (1967) titled one of his books The Art of the Soluble to illustrate that part of the creativity involved in science is finding the problem on the furthest edge of the frontier of human knowledge that will yield to empirical techniques.

Psychology itself provides many good examples of the development from the nonsolvable to the solvable. There are many questions (for instance, How does a child learn to speak the language of his or her parents? Why do we forget things we once knew? How does being in a group change a person's behavior and thinking?) that had been the subjects of speculation for centuries before anyone recognized that they could be addressed by empirical means. As this recognition slowly developed, psychology coalesced as a collection of problems concerning human behavior. Psychological issues gradually became separated from philosophy, and a separate empirical discipline developed.

Thus, the key step in understanding modern psychology is appreciating its implications as the empirical science of human behavior. Beginning students of psychology are often quite confused about just what distinguishes psychology as a discipline. It is not, for example, the focus on human behavior per se, because many other disciplines and professional groups are concerned in some way with human behavior: novelists, anthropologists, and so on. It is the fact that psychology studies human behavior scientifically that makes it unique as a discipline.

Many students major in the field of psychology because they want to "help people," but this again is not a defining feature of the field. "Helping people"- although a laudable goal-is really only one of many different applications of psychological knowledge, and many of these applications are outside of the helping professions entirely (for example, applications of psychological knowledge in advertising, in technology design, and in the military). Many other professionals engage in activities designed to "help people" (social workers, nurses, teachers, occupational therapists, pastoral counselors, and the like). Clinical and counseling psychology, however, base their therapeutic techniques on scientifically derived knowledge and evaluate the effectiveness of their techniques by scientific methods. This scientific approach is the only factor that differentiates the application of psychology in the human services domain. Nothing else distinguishes either the study or the practice of psychology. Thus, if psychology were not a science, it would simply have no reason to exist as a discipline.

TABLE 2. A Partial List of Publications Whose Articles Are Summarized in

Psychological Abstracts

Academic Psychology Bulletin            Child Behavior Therapy                  

Acta Psychologica                       Child Development                       

Addictive Behaviors                     Clinical Neuropsychology                

Adolescence                             Clinical Psychologist                   

Advances in Behavioral Pediatrics       Cognition                               

Advances in Behaviour Research &        Cognitive Psychology                    

Aging & Work                            Cognitive Therapy & Research            

American Behavioral Scientist           Contemporary Educational                

American Journal of Art Therapy         Psychology                              

American Journal of Clinical            Counseling Psychologist                 

American Journal of Clinical Hypnosis   Current Psychological Research          

American Journal of Community           Developmental Psychobiology             

American Journal of Family Therapy      Developmental Psychology                

American Journal of Mental Retardatio   Educational and Psychological           

American Journal of Psychology          Educational Psychology                  

American Journal of Psychotherapy       Environment & Behavior                  

American Psychologist                   European Journal of Social Psychology   

Animal Learning & Behavior              Genetic Psychology Monographs           

Annual of Animal Psychology             Hormones and Behavior                   

Applied ~Psycholinguistics              Human Development                       

Applied Psychological Measurement       Human Factors                           

Basic & Applied Social Psychology       Infant Behavior & Development           

Behavioral Assessment                   Intelligence                            

Behavioral and Brain Sciences           International Journal of Aging & Human  

Behavioral Disorders                    International Journal of Behavioral     

Behavioral Engineering                  International Journal of Eating         

Behavioral Science                      International Journal of Group          

Behavior Modification                   International Journal of                

Behavior Research Methods &             International Journal of Psychology     

Behavior Therapy                        International Journal of Sport          

Behaviour Research and Therapy          International Review of                 

Biological Psychology                   Journal for the Theory of Social        

Brain, Behavior & Evolution             Journal of Abnormal Child Psychology    

Brain and Language                      Journal of Abnormal Psychology          

British Journal of Clinical Psychology  Journal of Affective Disorders          

British Journal of Educational          Journal of Applied Behavioral Science   

British Journal of Mathematical &       Journal of Applied Developmental        
Statistical Psychology                  Psychology                              

British Journal of Social Psychology    Journal of Applied Psychology           

Bulletin of the British Psychological   Journal of Applied Social Psychology    

Bulletin of the Psychonomic Society     Journal of Behavioral Assessment        

Canadian Journal of Behavioral Science  Journal of Behavioral Medicine          

Canadian Journal of Psychology          Journal of Black Psychology             

TABLE 2 (cont.) A Partial List of Publications Whose Articles Are Summarized in

Psychological Abstracts

Journal of Child Psychotherapy          Law & Psychology Review                 

Journal of Clinical Child Psychology    Learning and Motivation                 

Journal of Clinical Psychology          Managerial Psychology                   

Journal of Community Psychology         Memory & Cognition                      

Journal of Comparative and              Merrill-Palmer Quarterly                
Physiological Psychology                                                        

Journal of Consulting and Clinical      Motivation and Emotion                  

Journal of Contemporary Psychotherapy   Multivariate Behavioral Research        

Journal of Counseling Psychology        Neuropsychologica                       

Journal of Cross-Cultural Psychology    New Directions for Methodology of       
                                        Social & Behavioral Science             

Journal of Economic Psychology          Organizational Behavior & Human         

Journal of Educational Psychology       Performance                             

Journal of Environmental Psychology     Perception                              

Journal of Experimental Child           Perception & Psychophysics              

Journal of Experimental Psychology:     Personality and Individual Differences  

Journal of Experimental Psychology:     Personality and Social Psychology       
Animal Behavior Processes               Bulletin                                

Journal of Experimental Psychology:     Personality Study & Group Behavior      
Leaming, Memory and Cognition                                                   

Journal of Experimental Psychology:     Personnel Psychology                    
Human Perception and Performance                                                

Journal of Experimental Social          Physiological Psychology                

Journal of General Psychology           Political Psychology                    

Journal of Genetic Psychology           Professional Psychology                 

Journal of  Individual Psychology       Physiology & Behavior                   

Journal of Instructional Psychology     Psychological Bulletin                  

Journal of Mathematical Psychology      Psychological Medicine                  

Journal of Mental Imagery               Psychological Record                    

Journal of Mind and Behavior            Psychological Research                  

Journal of Motor Behavior               Psychological Review                    

Journal of Nonverbal Behavior           Psychology in the Schools               

Journal of Occupational Psychology      Psychology of Music                     

Journal of Pediatric Psychology         Psychology of Women Quarterly           

Journal of Personality                  Psychometrika                           

Journal of Personality and Social       Psychophysiology                        

Journal of Personality Assessment       Quarterly Journal of Experimental       
                                        Psychology: Comparative and             
                                        Physiological Psychology                

Journal of  Psychohistory               Quarterly Journal of Experimental       
                                        Psychology: Human Experimental          

Journal of  Psycholinguistic Research   Rehabilitation Psychology               

Journal of Psychological Anthropology   Representative Research in Social       

Journal of Psychology & Theology        Scandinavian Journal of Behaviour       

Journal of Research in Personality      Scandinavian Journal of Psychology      

Journal of School Psychology            School Psychologist                     

Journal of Sport Psychology             School Psychology Review                

Journal of the American Psychoanalytic  Sensory Processes                       

Journal of the Experimental Analysis    Social Behavior & Personality           
of Behavior                                                                     

Journal of  Transpersonal Psychology    Social Psychology Quarterly             

Law & Human Behavior                    Vision Research