Question

Dr. Grodner is conducting an experiment on age-related changes in memory. He is comparing how well retirees and high school students perform on a memory task. In order to conveniently schedule research participants, he has the older adults come to the lab during the day, since they are retired. The students come to the lab in the evening, after they are finished with school and other activities. What is the problematic confound in this study?

A. It is unfair to compare older adults to younger adults, because older adults sometimes experience memory problems.
B. Dr. Grodner has not operationally defined memory for the purposes of his study.
C. If memory turns out to be something that varies by time of day, it is problematic that the older adults all do the study in the morning and the younger adults do the study at night.
D. Older adults have a lot more memories than younger adults, which confound the study.

Answer 1

Answer: C. If memory turns out to be something that varies by time of day, it is problematic that the older adults all do the study in the morning and the younger adults do the study at night.

Explanation: Confounding variables are additional variables that are not considered in an experiment but however, have an effect on the results of the experiment. For example, if the time of the day affects the memory, this is a confounding variable and it may explain the differences between the memory of the retirees and the school students rather than their age.

Without considering this possibility, the result of Dr. Grodner's experiment will be useless and invalid.