In Brendgan et al.'s study, what method was used to assess aggression in twins?

• A. Observational study
• B. Surveys
• C. Longitudinal study
• D. Experimental study

Answer: (C)

The correct answer highlights the use of a longitudinal study method in assessing aggression in twins according to Brendgan et al.'s research. Longitudinal studies involve repeated observations of the same variables over extended periods, allowing researchers to track changes and developments in behavior across different stages of life. In the context of studying aggression in twins, this method enables researchers to analyze how aggressive behavior may vary or remain stable over time, providing insights into both genetic and environmental influences.

This approach contrasts with observational studies, which typically involve collecting data at a single point in time without tracking changes. Surveys could gather self-reported data on aggression, but they might lack the depth and continuous observation provided by longitudinal methods. Experimental studies, while useful for establishing cause-and-effect relationships, generally involve manipulation of variables in a controlled setting, which may not be suitable for assessing naturalistic behavior like aggression over time. Thus, the longitudinal method offers a comprehensive view of aggression development in twins, making it the most appropriate choice for this research.