0.5 Experimenter Bias & the Placebo Effect

Experimenter Bias

The researcher’s expectations accidentally influence the study or results.

Observer-Expectancy Effect

Another name for experimenter bias.

Placebo Effect

Participants improve because they believe they are receiving treatment, even when the treatment itself is inactive.

Experimenter Bias = Researcher

The bias comes from the researcher’s expectations.

Placebo Effect = Participant

The effect comes from the participant’s belief.

Double-Blind Study

Neither the researcher nor the participant knows who received which condition.

Why Double-Blind Works

It helps control both experimenter bias and the placebo effect.

Pygmalion Effect

Expectations can influence how someone is treated, causing them to perform in the expected way.

Self-Fulfilling Prophecy

An expectation leads to behavior that helps make the expectation come true