In a longitudinal study that compares the effects of a memory training in a group of 9-year-olds and a group of 70-year-olds, selection by maturation could be a major threat to the internal validity of the study.

Question

Quizplus · Accepted Answer

Selection by maturation is a threat because the two age groups may naturally develop or decline in memory abilities at different rates over time, affecting the study's results.

In a Longitudinal Study That Compares the Effects of a Memory