Single-blind and Double-blind Procedures

What is a single-blind procedure?

A research method where the researcher doesn’t tell the participants which condition they are in.

What is a double-blind procedure?

A research method where neither the participants nor the researcher knows who is receiving a particular treatment.

What’s the point of a single-blind procedure?

To ensure that participants don’t bias the results by acting in ways they “think” they should act.

• Avoids demand characteristics

What is the point of a double-blind procedure?

To prevent bias in research results, particularly due to demand characteristics or the placebo effect (when participants show a change in behaviour because they believe they are receiving a treatment, not because the treatment actually works).

• Gives a way to reduce the investigator effects as the investigator is unable to unconsciously give participants clues as to which condition they’re in

What is a control group/condition?

Sets a baseline whereby results from the experimental condition can be compared to results from this one.

• If there’s a significantly greater change in the experimental group compared to the control group, then the researcher is able to conclude that the cause of effect was the IV