Falsifiability in psychology

Falsifiability in Psychological Science

For a theory to be scientifically valid, it must be testable. The criteria for 'testability' includes a theory's capability of being proven wrong as well as correct by means of an experiment structured upon the principles of the scientific method. This idea of 'testability' is at the core of the idea of "falsifiability." The need for a theory to be subject to the principle of 'falsifiability' is one reason that controls are used in scientific experiments: for example, a teacher could give every child candy before a test and assert that the candy was the reason the children did poorly. There is no way to prove the hypothesis wrong by determining if children in a control group, who did not eat the candy, did just as poorly as those who did consume the sugary substance. In contrast, if an experiment with a control group demonstrated universally poor scores, this would suggest that other causes were at the root of the student's poor grades. The theory of the candy causing the poor scores could thus be falsified.

Many scientifically dubious practices were used in the past because they were subject to tests that lacked falsifiability. For example, when individuals were 'blood let' for illnesses, sometimes they got better, sometimes they died. Doctors who defended blood-letting said that their treatment was the reason their patients got better and the patients who died would have died anyway. Of course, we know now that blood-letting is dangerous for most illnesses and the survivors recovered despite of, not because of the blood-letting treatment. However, for a long time, blood-letting was such a common medical practice it was never subject to empirical validation (Marian 2008).

It might be assumed that such medieval folk wisdom is confined to the past. Yet some individuals assert that psychology as a discipline lacks scientific falsifiability and thus is no 'science' at all (Lutus 2009). One of the philosopher Karl Popper's most eviscerating critiques of psychoanalysis was its lack of scientific verifiability -- the fact that an explanation could not be tested and thus 'always fit' the patient's condition because it could not be proved true or untrue.

The Freudian analysts emphasized that their theories were constantly verified by their 'clinical observations'. As for [the psychoanalyst] Adler, I was much impressed by a personal experience. Once, in 1919, I reported to him a case which to me did not seem particularly Adlerian, but which he found no difficulty in analyzing in terms of his theory of inferiority feelings, although he had not even seen the child. Slightly shocked, I asked him how he could be so sure. 'Because of my thousand-fold experience,' he replied; whereupon I could not help saying: 'And with this new case, I suppose, your experience has become thousand-and-onefold.'… they [the theories] always fitted, that they were always confirmed…it began to dawn on me that this apparent strength was in fact their [the theories'] weakness" (Popper 1953, p.2).

This universal 'explain-ability' is also seen in astrology, whereby a vague prediction of future events is given by a prognosticator. The theory cannot be proven or disproven. The statement is so broad it can be made to conform to almost any sequence of events. Astrology is not a science is because its theories cannot be empirically proven, anymore than a theory or aesthetic judgment about a literary test can be proven or unproven.

The problem of creating falsifiability in experiments where even the experimenter's subjective impressions can influence perceptions of the outcome is one of the challenges of psychology. Freudian theories do not pertain to anything testable, external, or 'real.' It is possible, according to Popper, that an individual can hate his or her mother due to repressed feelings -- or to an inferiority complex -- or to any number of reasons. Freudian psychology makes the human mind just as subjective and interpretable as a literary text. That is why, given psychology's aspirations as a science, Freud is now more often studied in literature classes than in psychology classes today. A study by the Journal of the American Psychoanalytic Association (JAPA),study, conducted a computer-based analysis of course descriptions at 150 public and private institutions that are highly ranked in U.S. News and World Report's college survey and "found that of the 1,175 courses that referenced psychoanalysis, more than 86% were offered outside psychology departments" (Cohen 2007).

However, psychology, even scientific psychology, presents falsifiability challenges not evident in the natural scientists. Some scientists might argue that Freud has been shown to be a poor theorist, given what has been revealed about the brain since Popper's day. If a depressive shows no improvement after years of Freudian therapy, but does show improvement after taking Prozac, that could be said to prove Freud wrong. Unfortunately, so many other external factors can affect a person's mood it is hard to attribute a single cause to a person's remission. It could be the drug or other conditions in the individual's environment. While large drug trials try to use large sample sizes as a way of reducing the influence of extraneous variables as well as use control groups who receive a placebo, the less observable and testable the phenomenon, the more difficult it is to measure. Even attempts to demonstrate improvement of children on an academic test after being prepared for the exam are contentious in terms of their ability to be externally validated. Tests of mood or psychological health are even more difficult to construct. Almost no conceivable ethical scientific test could confirm a broad-based psychological theory with the same level of falsifiability as a law of physics, given the levels of controls that would have to be imposed upon the human subjects.