Читать книгу Methods in Psychological Research - Annabel Ness Evans - Страница 76

The dependent variable (DV) in psychological research is some response measure that we think will be influenced by our IV. Reading comprehension might be a DV, and we might measure the number of correct answers on a comprehension quiz as our operational definition of reading comprehension. Or we might measure depression by having participants rate how they feel on a scale. In an experiment, the DV can be thought of as the effect in a cause–effect relationship.

When we are trying to determine patterns of responding by measuring variables, we are always concerned with the natural variability of participants’ responses. Of course, our goal in research is to explain some of this variability. For example, if your research question is “Do students who read a lot understand better what they read?” then you are in a sense trying to account for the variability in student reading comprehension by determining how much they read. This is the variability that you are interested in explaining with your relationship. However, some variability is outside our primary interest. For example, if we are trying to determine whether classroom technology improves learning, we are not interested in variables such as temperature of the classroom, time of day of the class, or ability of the instructor. Rather, we want to control or account for these variables so that we can better assess the effect of our primary variable (i.e., technology).

If other variables that might have affected the DV have been controlled in some way, the researcher can conclude that differences in the DV are a result of, or caused by, the IV manipulation. This is the core of the experimental design, and to the degree that other variables have been controlled, we can be more confident in making causal inferences with these designs than we can with nonexperimental research. We discuss the various ways to control these other variables in Chapter 4.