In a study of the effectiveness of a treatment for depression,a psychologist assessed patients' symptoms of depression using a reliable questionnaire both before and for several months after treatment.The results indicated that the patients experienced a decrease in their symptoms over the 8-month time period of the study.One threat to internal validity the researcher should consider is
A) maturation.
B) regression.
C) testing.
D) all of these

Question

Quizplus · Accepted Answer

All three potential threats to internal validity - maturation, regression, and testing - could potentially affect the results of the study. Maturation refers to changes in the participants over time that are unrelated to the treatment, such as natural healing or development. Regression suggests that people who experience extreme symptoms at the beginning of the study are likely to experience less severe symptoms over time, even without the treatment. Finally, the act of testing itself can influence participant behavior, as they may become more aware of their symptoms and change their responses accordingly.

In a Study of the Effectiveness of a Treatment for Depression,a