Dr. Mo T. Vadar, a professor of psychology at a respected university, is planning a study of the factors that affect the motivation of employees. Dr. Vadar is concerned that the results of his experiments may be misleading because employees in an experimental group tend to behave differently when they know they are being studied. This concern shows that Dr. Vadar is aware of the:

Hawthorne effect.

Explanation:

The Hawthorne effect can be defined as the proneness of people to work harder when they know they are the participants in an experiment. The Hawthorne effect was first discovered by researcher Henry A. Landsberger in the 1950s. Landsberger defined the tendency for working harder and improved performance by the workers for the short-term as the Hawthorne effect.

In the given case, Dr. Mo T. Vedar is aware of the Hawthorne effect as he knows that results can be misleading. Dr. Mo T. Vedar knows that people tend to work harder and show performance improvement when they are under observation or a participant in an experiment.

Thus, the Hawthorne effect is the correct answer.

the answer to this question is d