Final answer:
A researcher interested in studying the evolution of a topic over time and societal influences would likely use a longitudinal study, which observes the same individuals over an extended period to track changes.
Step-by-step explanation:
A researcher interested in how a topic has changed over time and the influence of cultural and societal shifts will most likely consider a longitudinal study. Longitudinal research involves tracking the same group of individuals over a long period of time, allowing for the observation of changes and developments within the same cohort. This approach can unveil how beliefs or behaviors evolve as individuals age and as societal norms change. On the other hand, a cross-sectional study would compare different groups at one point in time, which could reflect generational differences stemming from diverse cultural experiences rather than changes over time.