The placebo effect is an example of a (n) experimenter bias. participant bias. random assignment bias. random selection bias.

participant bias

Step-by-step explanation:

Participant bias is sometimes called as subject bias. it is referred to as the tendency of a subject that forces them to act in an experiment. it is held because that they think researchers is looking up to them to act. it occurs only when the subject has detail knowledge about the study or project.

Participant bias is a subject initiative to know about the inner thought of the researcher so the subject acts according to what the researcher wants to hear.