Investigator Effects and Demand Characteristics

Question 1

What are investigator effects?

Answer 1

Also known as experimenter bias.

Anything that the investigator does which has an effect on the PPs performance in a study other than what was intended.

Conscious or unconscious e.g. a really good looking experimenter.

Question 2

How can investigator effects be eliminated?

Answer 2

By implementing a double blind procedure.

Question 3

How do investigator effects occur?

Answer 3

Physical characteristics of the investigator, e.g. male participants may be unwilling to admit sexist views in front of a female researcher.

Less obvious personal characteristics, e.g. participants may respond differently to someone with a stern voice.

Investigators may be unconsciously biased in their interpretation of the data and find what they expect to find.

Question 4

What is a single-blind procedure?

Answer 4

Means that PPs are not informed of the condition that they are in and this helps to eliminate demand characteristics.

Question 5

What is a double-blind procedure?

Answer 5

Means that neither the PPs nor the experimenter knows the precise aims of the study.

This reduces experimenter effects as it prevents investigators from giving PPs clues (consciously or subconsciously) as to which condition they are in.

Question 6

What are demand characteristics?

Answer 6

Interactions between researchers and participants and that affect research findings.

There are several features of research studies that enable participants to guess what a study is about and what is expected of them.

Question 7

Give 2 examples of demand characteristics.

Answer 7

Guessing the purpose of the research and trying to please the researcher by giving the ‘right’ results.

Guessing the purpose of the research and trying to annoy the researcher by giving the wrong results; this is called the ‘screw you effect’.

Acting unnaturally out of nervousness or fear of evaluation.

Acting unnaturally due to social desirability bias.