Which of the following best describes the difference between an observational study and an experiment in psychological research?

• A. Observational studies require informed consent, but experiments do not.
• B. Experiments are only used for qualitative data, while observational studies are used for quantitative data.
• C. An observational study always uses random assignment, while an experiment never does.
• D. In an observational study, researchers do not manipulate variables but simply observe and record behavior, whereas in an experiment, researchers actively manipulate one or more independent variables to determine their effect on dependent variables.

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the key terms involved. An observational study is a research method where the researcher observes and records behavior without manipulating any variables. An experiment, on the other hand, involves the active manipulation of one or more independent variables to observe their effect on dependent variables.
2. Step 2: Identify the role of variable manipulation. In an experiment, the researcher deliberately changes the independent variable(s) to see how it affects the dependent variable(s). In an observational study, no such manipulation occurs; the researcher only observes naturally occurring behaviors or outcomes.
3. Step 3: Consider the purpose of each method. Observational studies are often used when manipulation is unethical or impractical, while experiments are designed to establish cause-and-effect relationships by controlling variables.
4. Step 4: Evaluate the answer choices based on these definitions. The correct description should highlight the presence or absence of variable manipulation as the main difference between the two methods.
5. Step 5: Conclude that the best description is that observational studies involve no manipulation of variables, only observation, whereas experiments involve active manipulation of independent variables to study their effects on dependent variables.