gender differences. In one treatment study, the control group was instructed by young, inexperienced technicians, whereas the experimental group was instructed by an older, more experienced professional. This difference may have produced a confound in the results.
Some confounds can be prevented or controlled. However, other factors can never be controlled. You cannot control world events, but you can ask whether there is any reason to believe that a particular event that took place inside or outside of the laboratory could have influenced one group more than another and thus introduced a confound.
Research Hypothesis
After ruling out the null hypothesis and the confound hypothesis, we can assume that the results reflect the action of the IV. Our next step is to consider what this means. We begin to generalize from our set of data and consider both the implications of our results for other groups of people and the theoretical implications of the data. Sometimes we are led to new ideas, which in turn generate new research hypotheses, which can be investigated with additional experiments.
Figure 3.8 Four Major Steps in the Experimentation Process
Figure 3.8 presents a simplified outline of this procedure, which reflects the evolutionary nature of science. The steps include (1) the development of the hypothesis, (2) the translation of this hypothesis into a research design, (3) the running of the experiment, and (4) the interpretation of the results. You will notice that there is also an arrow from Step 4 back to Step 1. Researchers take the results and interpretations of their studies and create new research studies that refine the previous hypotheses.
In psychological research, we have some powerful techniques to help us achieve this goal. Unlike the detective who must always reconstruct events after the fact, the researcher has the advantage of being able to create a new situation in which to test ideas. This is comparable to a homicide detective’s being able to bring a dead man back to life and place him in the presence of each suspect until the murder is reenacted. Such a reenactment might lack suspense and not make it in prime time, but it would increase the certainty of knowing who committed the murder.
Increased certainty is a large part of the experimental process. Scientists increase certainty by creating an artificial situation—the experiment—in which important factors can be controlled and manipulated. Through control and manipulation, participant variables may be examined in detail, and the influence of one variable on another may be determined with certainty. The Cultural LENS below describes randomized controlled trials (RCTs), examining treatments for mental illness in low- and middle-income countries.
Cultural Lens
Randomized Controlled Trials of Global Mental Health Treatments in Low- and Middle-Income Countries
A mental health worker meets with patients and their families.
The Sydney Morning Herald/Contributor/Fairfax Media/Getty Images
There is a large difference in mental health treatment in high-income countries like the United States, England, Germany, France, Japan, and Australia as compared with low- and middle-income countries such as India, Pakistan, China, Chile, Mexico, and many countries in Africa. In high-income countries, there are a larger number of professionals who can deliver mental health services. Treatment procedures such as medications and psychological therapies have also been developed and tested in these higher-income countries. In contrast, there are fewer mental health professionals in low- and middle-income countries. Thus, family members and nonprofessionals are often involved in the treatment of mental disorders. It is critical that low-income countries use treatments that are both effective and available at low costs.
Treatment research does exist that suggests that local communities can offer effective treatment for depression and schizophrenia. In low- and middle-income countries, these disorders often go untreated. This LENS focuses on depression, although similar positive results have been shown for schizophrenia, particularly in China. Depression is a common disorder throughout the world, so having effective treatments for depression worldwide is critical. Effective treatments are available for depression in terms of both psychotherapy and antidepressant medication. Both of these approaches can be delivered in a relatively inexpensive manner in low-income countries using community individuals with training in that one procedure. These trained individuals also have the advantage of understanding the culture in which the clients live. Not only does the treatment improve the individuals who have the disorder and their community, but it also has a positive effect on the economy by reducing days lost from work. A number of researchers have begun to evaluate the treatment of depression in low- and middle-income countries (Patel et al., 2007). Some examples of this research are shown in Table 3.1. To achieve the greatest scientific benefit, it is important that the participants in the experiment be assigned to groups using an RCT design. That is, the participants in the study must be randomly assigned to the treatment group.
Thus, if the person’s family and community can be involved in the treatment, the results are more positive. Performing treatment studies in low- and middle- income countries is not only of benefit to the community but also helps the researchers to establish the generalizability of the treatment worldwide. Similar research with medical disorders in Africa by the Gates Foundation also suggests that successful interventions developed in low-income countries can be applied in low-income areas of the United States.
Thought Question: What are the challenges and benefits involved in delivering and researching mental health treatment in low- and middle-income countries?
Table 3.1
RCT = Randomized controlled trial.
Source: Reprinted from Patel et al., “Treatment and prevention of mental disorders in low-income and middle-income countries,” The Lancet, Vol. 370, 991–1005, Copyright 2007, with permission from Elsevier.
Concept Check
What are five factors critical to enabling sound inference in determining the relation between the IV and the DV in an experiment?
Why is randomization important to selecting participants and assigning them to groups in an experimental study?
What is a match subjects design? When would you use this design instead of a randomized study?
What roles do the following hypotheses play in interpreting experimental results?Null hypothesisConfound hypothesisResearch hypothesis
Other Types of Experimental Designs and Research Considerations
In this section, I want to look at a few additional types of research that are used in the study of psychopathology. These include the study of a single person in an experimental manner, research that follows a number of individuals over a period of time, research that seeks to determine how frequently a disorder is present in a population, and research involving genetics. This section will conclude with a discussion of clinical and statistical significance and the importance of replication.
Single-Subject
