In developmental psychology, changes in behavior and cognitive processes over time are primarily studied using which research design?

• A. Cross-sectional research design
• B. Single-blind experimental design
• C. Case study method
• D. Longitudinal research design

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the key focus of the question, which is about studying changes in behavior and cognitive processes over time in developmental psychology.
2. Step 2: Recognize that to study changes over time, the research design must involve observing the same subjects repeatedly at different points in time.
3. Step 3: Review the options: Cross-sectional design compares different age groups at one point in time, Single-blind experimental design controls bias in experiments but does not focus on time, and Case study method involves in-depth analysis of a single subject or group without necessarily tracking changes over time.
4. Step 4: Identify that the Longitudinal research design involves following the same individuals over an extended period to observe developmental changes, making it the most appropriate design for this purpose.
5. Step 5: Conclude that the Longitudinal research design is the correct choice for studying behavioral and cognitive changes over time in developmental psychology.