Which threat to internal validity involves the effects of time on participant characteristics?

The correct answer, maturation/passage of time, refers to the natural changes that occur in participants over time that can influence the outcomes of a study. In the context of research, as time progresses, individuals may experience various physical, cognitive, emotional, or social changes that can affect their responses or behaviors. For instance, as participants grow older or undergo life experiences, these factors can impact the results of a study focused on developmental changes or behavioral assessments.

Understanding maturation is crucial for researchers because if these changes are not accounted for, they may incorrectly attribute differences in outcomes to the experimental intervention rather than to normal developmental processes or changes associated with aging. This can lead to misleading conclusions about causal relationships within the research.

While statistical regression, experimental mortality, and diffusion of intervention methods are important considerations in research design, they pertain to different aspects of internal validity. Statistical regression deals with the tendency of extreme scores to move closer to the mean upon retesting, not directly tied to time effects. Experimental mortality involves the loss of participants over time, which could skew results but is distinct from the gradual changes in individuals themselves. Diffusion of intervention methods refers to the spread of treatment effects among control groups or unintended recipient groups rather than the inherent changes in participants as time