Final answer:
Psychologists employ the double-blind procedure to avoid both participant and experimenter bias, ensuring neither party's expectations influence the results of an experiment.
Step-by-step explanation:
To prevent participants in an experiment from trying to confirm the researchers' predictions, psychologists sometimes employ the double-blind procedure. This means both the researchers and the participants are unaware of who is assigned to which group (experimental or control), thereby preventing bias from both parties.
In a double-blind study, controlling for both experimenter and participant expectations is crucial. This mitigates the placebo effect, which occurs when an individual's expectations affect the outcome. Blinding both subjects and researchers ensures that behaviors and outcomes are not influenced by preconceived notions or expectations about the treatment or the study's purpose.
A placebo is often used in control groups to balance the effects of being in an experiment with the active treatments. This is a component of blinding in randomized experiments designed to reduce bias, allowing for a more accurate assessment of the efficacy of the treatment being tested.