explain, predict, and control the subject matter of the discipline. Science, therefore, is a way of thinking and a way of doing things. Scientists view the world differently than many nonscientists do. The process of scientific inquiry involves certain assumed principles or tenets about how the world works.
The Tenets of Science
The scientific approach to discovering truth assumes several fundamental principles about how the world works and demands that certain criteria be met. Some people misunderstand some of these tenets of science. Perhaps the most misunderstood is the doctrine of determinism.
Determinism
Determinism is a doctrine of belief that events have natural causes. For psychologists, the events we are interested in are behaviors of humans. When we apply this doctrine to psychology, then, we assume that human behavior is determined or caused by natural phenomena, not supernatural events. In other words, we believe that behavior is neither random nor under the control of nonnatural events. Many people confuse this doctrine with another, predeterminism. They are not the same. To say that behavior is determined by natural events is not to say that our behavior is somehow predetermined or predestined. Some religious approaches do have a predeterministic bent, but psychology does not.
To say that human behavior is determined is to say that humans behave for reasons that can be understood in terms of natural laws of the universe. We may not know what those laws are in any particular case, but we assume that those laws are operating nonetheless.
Empiricism
Scientists, including psychologists, rely on real evidence, empirical data, to confirm or refute claims. Intuition, faith, and even logic are not enough. There must be empirical support before a scientist will accept a claim.
Replicability
Scientists require that findings be replicable before they are accepted. A single finding may be just a fluke and not reliable. This is of particular importance in psychology because our subject matter, human behavior, is so variable. Behavior varies among people in the same or similar situations. Indeed, the behavior of one person varies even in what appear to be identical conditions.
Falsifiability
For scientists, hypotheses and theories must be falsifiable through empirical research. They must be testable such that they could be shown to be false. Some theories are just not refutable. Consider Freud’s theory about repression. The assumption is that psychological problems of adults are rooted in childhood trauma. Is this hypothesis falsifiable? We don’t think so. If an adult can recall and describe a childhood trauma, the Freudian will conclude that his or her current problems developed because of the trauma. If an adult cannot recall any trauma, the Freudian concludes that he or she has repressed the events into his or her unconscious mind. This hypothesis cannot be proven wrong. This hypothesis, like much of Freud’s theory, is pseudoscience. Consider another example of pseudoscience. A psychic who is brought into a laboratory and asked to demonstrate his powers in a controlled setting and who cannot do so claims that the air of skepticism of the researchers is responsible for interfering with the psychic forces. The psychic wins either way. His powers are proven when he demonstrates evidence of psychic ability. His powers, however, are not disproved when he does not.
Parsimony
A scientist looks for the simplest explanation for a phenomenon. Parsimony means the quality of being sparing or frugal. If two explanations account for similar amounts of data but one explanation requires fewer assumptions, the scientist will favor that explanation. This is not to say that the explanation will be simple. There is nothing simple about the molecular events underlying synaptic transmission or the many factors that might cause a new parolee to reoffend. Parsimony means that few assumptions are made; instead, our explanation must be based on scientific evidence. In general, the scientist looks for the explanation that accounts for the most data with the fewest assumptions.
We have discussed the tenets of science, but what makes a science a science? You may have heard the terms hard and soft science. These terms, which we disapprove of, classify science by its subject matter. Chemistry is considered by some to be a hard science and psychology a soft science. Some people claim that chemistry is a more rigorous science than psychology. Why do they claim this? We think it lies in the variability of the behavior of the subject matter, not in the rigor of the method used. Molecules are less variable in behavior than humans are, but chemistry outside the laboratory can be just as variable as psychology. A discipline is a science if the scientific method is the primary method used in the research process.
Conceptual Exercise 1B
1 John is a volunteer at a local emergency room (ER). The medical personnel tell John that on nights when there is a full moon, there are many more shooting and knifing cases in the ER. The workers believe that the moon is the cause. John keeps records and finds that, indeed, on full-moon nights, there are many more of these cases that come into the ER than on nights with no full moon. He contacts other ERs and finds that they too report many more of these cases on those nights. He concludes that the full moon has powers that increase criminality in people. What tenet of science has John failed to follow?
2 A student conducted a survey on the Internet to measure attitudes about funding of animal research. She found that people are opposed to the use of animals in research on cosmetic products. Another student used an interview method and learned that her sample had no such opposition to the use of animals in cosmetic testing. What tenet of science is the problem here?
3 Mary, a social worker, has observed that evil people do evil things and good people do good things. She has seen many examples of this in her practice, and her colleagues report that they have, too. When a person does evil, Mary claims it is the evil within him or her that caused this behavior. Likewise, good behavior is evidence of goodness. What tenet of science has Mary ignored?
The Scientific Method
The method of science involves logical steps toward finding truth. The steps are as follows:
1 Assume a natural cause for the phenomenon (i.e., determinism)
2 Make an educated guess about the cause (i.e., generate a testable hypothesis)
3 Test your guess
4 Revise your hypothesis
5 Retest your guess
6 Make a conclusion
Consider a psychology student who lives in a small town in southern Alabama. She has noticed that people of the town often visit a recluse who lives outside of town when they have aches and pains. The townspeople believe that the recluse is a witch who has supernatural healing powers. Our psychology student decides to apply the scientific method to assess the beliefs of the townspeople. (This example is a variation on one given by Willie Runquist, the PhD supervisor of Annabel Evans.)
Step 1. She assumes that there is a natural explanation for her observation that the townspeople do appear to feel better after they visit the witch.
Step 2. She has noticed that the witch always gives the townspeople a potion to drink when they visit, and she assumes that the potion contains something medicinal. She has discovered that the potion contains eye of newt, desiccated bat wings, and ground poppy seeds. She decides that the eye of newt might be the active medicinal ingredient.
Step 3. She finds a way to substitute an inert substance for the witch’s supply of eye of newt. For the next week, she observes the effects of the potion on the visitors. She finds that they report that they feel better as often as they