Extraneous variables

Question 1

What is an extraneous variable?

Answer 1

Any variable other than the independent variable that affects the dependent variable.

Question 2

What are the types of extraneous variables?

Answer 2

Situational
Participant
Investigator effects
Demand characteristics

Question 3

What is a situational variable?

Answer 3

Features of a research situation that may influence participants behaviour.
Order effects
Time of day
Heat

Question 4

What are order effects?

Answer 4

The order in which participants complete experimental conditions.

Question 5

Order effects: what is the practice effect?

Answer 5

Participants get better at the experiment as they practice.

Question 6

Order effects: what is the fatigue effect?

Answer 6

Participants get slower/worse as they get tired/bored.

Question 7

How can you solve order effects?

Answer 7

Counterbalancing (ABBA)
1st group does AB
2nd group does BA

Question 8

What does it mean to standardise an experiment?

Answer 8

Keep everything the same for every participant.
Standardised procedure
Standardised instructions
Counterbalancing

Question 9

What are participant variables?

Answer 9

The ways in which each participant varies from the other and how this could affect the results.
Mood
IQ
Anxiety
Concentration

Question 10

Controlling participant variables.

Answer 10

Depends on experimental design

Question 11

What are investigator effects?

Answer 11

The experimenter unconsciously conveys to participants how they should behave: experimenter bias.
The experimenter is often unaware of the influence which they are exerting, but they may have an influence nevertheless.

Question 12

Controlling investigator effects: double blind design

Answer 12

Both the participant and the person conducting the experiment are blind of the aims and/or hypothesis.
The experimenter may be unaware which variable the participant is involved in.

Question 13

Controlling investigator effects: inter-rater reliability

Answer 13

Independent raters rate the same behaviour as the researcher and check for agreement.

Question 14

What are demand characteristics?

Answer 14

If participants know/guess the experimenter’s intention they may change their behaviour accordingly.
They may think they are being helpful but it’s not.

Question 15

What is the screw-you effect?

Answer 15

This when a participant is purposefully trying to be unhelpful.

Question 16

What is the Hawthorne effect?

Answer 16

This is when a participant changes their behaviour just because they are being watched.

Question 17

Controlling demand characteristics: single blind design

Answer 17

The participant is unaware of which condition they are in or the research aims. This prevents the participants from seeking clues about the aims and reacting to them.

Question 18

Controlling demand characteristics: deception

Answer 18

Lying about the aims of the study and/or using distracting questions.

Question 19

What is a confounding variable?

Answer 19

When extraneous variables are not controlled by the experimenter, they become confounding variables that damage the validity of the experiment.