According to the American Psychological Association, when is it acceptable for a psychological researcher to coerce participants?

never

Explanation:

Under the American psychological association guidelines for psychology research, participants of research are never to be coerced for research purposes. This is because any action in this resemblance will greatly hinder the objectives of research or even largely affect results of research. This goes against their ethical guidelines.

Not Acceptable

Explanation:

According to the code of Ethical Standard of American Psychological Association which applies to the clinical psychological researchers; it clearly mentioned that the researchers should not coerce the participants. Researchers cannot offer excessive or inappropriate financial or other awards as mentioned in code of ethical standards.