What you’ll learn to do: examine how descriptive, correlational, and experimental research is used to study abnormal behavior

As you learned in the previous module, the scientific approach led to major advances in understanding abnormal behavior and treating mental disorders. The essence of the scientific method is objectivity. It expresses the idea that the claims, methods, and results of science are not, or should not be, influenced by particular perspectives, value commitments, community bias, or personal interests, to name a few relevant factors. In addition, researchers must always be open to alternative explanations that could account for their findings. Many researchers have a personal interest in what they are studying and they become involved in the pursuit of knowledge in areas that relate to experiences in their own lives, particularly in the field of abnormal psychology. Clinical psychologists may wonder whether a particular kind of experience led to an individual’s symptoms, whether a certain treatment will be effective to treat the symptoms of a disorder, or they may speculate about the role of genetic predispositions. In either case, when conducting research, however, they do not let their personal biases get in the way of collecting the data or interpreting the findings. The ideal approach to answering these questions involves a progression through a set of steps in which psychological researchers propose a hypothesis, conduct a study, and collect and analyze the data. 

In this section, we will take a closer look at how to examine research and the main types of studies used: descriptive, experimental, and correlational. Descriptive, or qualitative, methods include the case study, naturalistic observation, surveys, epidemiological research, archival research, longitudinal research, and cross-sectional research.

When scientists passively observe and measure phenomena, it is called correlational research. Here, psychologists do not intervene and change behavior as they do in experiments. In correlational research, they identify patterns of relationships, but usually cannot infer what causes what. Importantly, with correlational research, you can examine only two variables at a time, no more and no less.