Factors affecting validity

Question 1

What are Demand Characteristics?

Answer 1

• Participants want to be helpful and therefore they pay attention to cues in the experimental situation that may guide their behaviour.
• Orne Invented the term Demand characteristics to describe the effect of expectations and defined them in the following way;
  “the totality of cues that convey the experimental hypothesis to the (participant) become determinants of the (participants) behaviour.
  Orne, 1962
• Watching a football game at home you sit relatively quietly, but at a football ground you would chant and jump up and down.
• These different situations create different expectations and ‘demand’ different behaviours.

Question 2

What is experimental demand characteristics.

Answer 2

• in an experiment, participants are often unsure about what to do. They actively looks for clues as to how they should behave in that situation.
• These clues are demand characteristics- which collectively convey the experimental hypothesis to participants.
  e. g.
• a participant is given two memory tests (repeated measures), one in the morning and one in the afternoon, Participants might try to guess why they are being given two tests and correctly work out that the study is looking at the effect of time of day on performance. this might lead the participant to try to perform the same on each test.
• The result is that the participants do not behave as they would usually. They have altered their behaviour as a consequence of cues in the research situation. Thus demand characteristics may act as an extraneous (confounding) variable.

Question 3

What are the four threats to validity?

Answer 3

• Demand characteristics
• experimental demand characteristics
• researcher bias
• indirect investigator effects.

Question 4

What is researcher bias?

Answer 4

• researcher bias refers to information (other than IV) from a researcher that encourages certain behaviours in the participant which might lead to a fulfilment of the investigators expectations
• such cues act as an extraneous or confounding variable.
• investigators unconsciously encourage participants by, for example, spending more time with one group of participants or being more positive with them.
• for example, research has found that males are more pleasant and friendly with female participants than with other male participants.

Question 5

What is indirect investigator effects?

Answer 5

• There also indirect investigator effects, such as the investigator experimental design effect. The investigator may operationalise the measurement of variables in such a way that the desired result is more likely, or may limit the duration of the study for the same reason.
• The investigator loose procedure effect refers to situations where an investigator may not clearly specify the standardised instructions and/or procedures, which leaves room for the results to be influenced by the experimenter.

Question 6

How to deal with Validity in experiments?

Answer 6

• single blind design
• double blind design
• experimental realism

Question 7

What is single blind design?

Answer 7

• in a single blind design the participant is not aware of the research aims, this prevents the participant fro seeking cues about the aims and reacting to them.

Question 8

What is double blind design?

Answer 8

• in a double blind design both the participant and the person conducting the experiment are ‘blind’ to the aims/hypotheses. therefore the person conducting the investigation is less likely to produce cues about what he/she expects.

Question 9

What is experimental realism?

Answer 9

• if the researcher makes an experimental task sufficiently engaging the participant pays attention to the task and not the fact that they are being observed.

Question 10

OTHER EXTRANEOUS VARIABLES; Participant variables?

Answer 10

• A participant variable is any characteristic of individual participants. Participant variables are not the same as participant effects. Demand characteristics are an effect of participants behaviours (participant effect)), whereas a participant variable is a characteristic of participants.
• Participant variables act as extraneous variables only if an independent groups design is used. When a repeated measures design is used, participant variables are controlled. In a matched pairs design participant variables are hopefully controlled.
• Participant variables include age, intelligence, motivation, etc. Students often identify gender as an extraneous variable and it may be. For example Alice Eagly (1978) reported tat women may be more conformist than men.

Question 11

Situational Variables?

Answer 11

• Situational Variables are those features of a research situation that may influence participants behaviour and thus act as Extraneous variables or confounding variables.
• One example of a situational variable is order effects, Improved participants performance may be due to practice (a confounding variable) rather than the IV.
• Situational variables are only confounding if they vary systematically with the IV, for example if all members of one group are tested in the morning and all members of the second group are tested in the afternoon.