Which of the following best describes how a longitudinal study differs from a typical within-group research design in developmental psychology?

• A. A longitudinal study follows the same participants over an extended period to observe changes, while a typical within-group design compares differences among participants at a single point in time.
• B. A longitudinal study collects data only once, while a within-group design collects data multiple times.
• C. A longitudinal study compares different age groups at one time, whereas a within-group design examines only one age group.
• D. A longitudinal study uses random assignment to groups, while a within-group design does not.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the definition of a longitudinal study in developmental psychology. A longitudinal study involves observing the same participants repeatedly over an extended period to track changes and development within those individuals.
2. Step 2: Understand what a typical within-group research design entails. In a within-group design, the same group of participants is tested under different conditions or at one point in time, focusing on comparisons within that group rather than over time.
3. Step 3: Compare the key difference: longitudinal studies emphasize tracking changes over time within the same individuals, while within-group designs typically compare conditions or variables at a single time point within the same group.
4. Step 4: Evaluate the incorrect options by identifying why they do not accurately describe the difference. For example, longitudinal studies do not collect data only once; they collect data multiple times. Also, longitudinal studies do not necessarily use random assignment, and they do not compare different age groups at one time (that would be a cross-sectional study).
5. Step 5: Conclude that the best description is that longitudinal studies follow the same participants over time to observe changes, whereas typical within-group designs compare differences among participants at a single point in time.