what is harm to participants?
p's should not be harmed, either physically or psychologically when participating in research.
in practice, however, p's often suffer distress/pain during the course of an exp and considered acceptable as long as:
the harm is unacceptable, and the study could not carried out in any other way.
the harm is short-term and relatively minor.
the p's are not allowed to leave the study w/ any residual harm or distress.