Responding to a substance like a sugar pill as if it were a drug is called

Responding to an inert sugar pill as if it were a real drug is called the placebo effect.

An extraneous factor is an unwanted variable that may confound results, not this response itself.

Variability refers to the spread of scores, unrelated to reacting to a dummy treatment.

The regression effect is the drift of extreme scores toward the mean on retesting.

Placebo control groups are used to separate a treatment's true effect from expectation.

Double-blind designs keep both participant and experimenter unaware of the assignment.