Before conducting any experiment on humans, a psychological investigator must obtain

A) demand characteristics.
B) permission from the American Psychological Association.
C) a normal distribution.
D) informed consent.

Psychological Investigator

An individual who conducts studies and experiments to understand human behavior and mental processes.

Informed Consent

A process ensuring that a participant is fully aware of and understands the potential risks and benefits of their participation in a study or treatment.

Experiment

A method of research in the sciences or social sciences in which variables are manipulated to observe their effects on other variables.