RM: Experimental methods

Question 1

What are the three key concepts?

Answer 1

The aim, hypothesis and experimental method.

Question 2

What is the aim?

Answer 2

A general expression of what the researcher intends to investigate.

Question 3

What is an hypothesis?

Answer 3

A statement of what the researcher believes to be true. Should be operationalised, i.e. clearly defined and measurable. Two types: directional and non-directional.

Question 4

What are the two types of hypothesis?

Answer 4

Directional hypothesis and non-directional hypothesis.

Question 5

What is a directional hypothesis?

Answer 5

States whether changes are greater or lesser, positive or negative etc.

Question 6

What is a non-directional hypothesis?

Answer 6

Doesn’t state the direction, just that there is a difference, correlation, association.

Question 7

What is an experimental method?

Answer 7

A researcher causes the independent variable (IV) to vary and records the effect of the IV on the dependent variable (DV). There are different levels of the IV.

Question 8

What are the some research issues?

Answer 8

Extraneous variables, confounding variables, demand characteristics and investigator effects.

Question 9

What are extraneous variables?

Answer 9

They are ‘nuisance’ variables that do not vary systematically with the IV. A researcher may control some of these.

Question 10

What are confounding variables?

Answer 10

They change systematically with the IV so we cannot be sure if any observed change in the DV is due to the CV or the IV. CVs must be controlled.

Question 11

What are demand characteristics?

Answer 11

Refers to any cue from the researcher or research situation that may reveal the aim of the study.

Question 12

What are investigator effects?

Answer 12

Any effect of the investigator’s behaviour on the outcome of the research (the DV).

Question 13

What are the research techniques?

Answer 13

Randomisation, standardisation, control groups, single blind and double blind.

Question 14

What is randomisation?

Answer 14

The use of chance when designing investigations to control for the effects of bias.

Question 15

What is standardisation?

Answer 15

Using exactly the same formalised procedures for all participants in a research study.

Question 16

What are control groups?

Answer 16

Control groups are used for the purpose of setting a comparison. They act as a ‘baseline’ and help establish causation.

Question 17

What is single blind?

Answer 17

A participant doesn’t know the aims of the study so that demand characteristics are reduced.

Question 18

What is double blind?

Answer 18

Both participant and researcher don’t know the aims of the study to reduce demand characteristics and investigator effects.

Question 19

What are the three experimental designs?

Answer 19

Independent groups, repeated measures and matched pairs.

Question 20

Describe the independent groups experimental design.

Answer 20

One group do condition A and a second group do condition B. Participants should be randomly allocated to experimental groups.

Question 21

What are the strengths of the independent groups experimental design?

Answer 21

NO ORDER EFFECTS: participants are only tested once so can’t practice or become bored/tired. This controls an important CV.
WILL NOT GUESS AIM: participants only tested once so are unlikely to guess the research aims. Therefore behaviour may be more ‘natural’.

Question 22

What are the limitations of the independent groups experimental design?

Answer 22

PARTICIPANT VARIABLES: the participants in the two groups are different, acting as EV/CV. May reduce the validity of the study.
MORE PARTICIPANTS: need twice as many participants as repeated measures for same data. More time spent recruiting which is expensive.

Question 23

Describe the repeated measures experimental design.

Answer 23

Same participants take part in all conditions of an experiment. The order of conditions should be counterbalanced to avoid order effects.

Question 24

What are the strengths of the repeated measures experimental design?

Answer 24

PARTICIPANT VARIABLES: the person in both conditions has the same characteristics. This controls an important CV.
FEWER PARTICIPANTS: half the number of participants is needed than in independent groups. Less time spent recruiting participants.

Question 25

What are the limitations of the repeated measures experimental design?

Answer 25

ORDER EFFECTS ARE A PROBLEM: participants may do better or worse when doing a similar task twice. Reduces the validity of the results.
PARTICIPANTS MAY GUESS AIMS: participants may change their behaviour. This may reduce the validity of the results.

Question 26

Describe the matched pairs experimental design.

Answer 26

Two groups of participants are used but they are also related to each other by being paired on participant variable(s) that matter for the experiment.

Question 27

What are the strengths of the matched pairs experimental design?

Answer 27

PARTICIPANT VARIABLES: participants matched on a variable that is relevant to the experiment. This enhances the validity of the results.
NO ORDER EFFECTS: participants are only tested once so no practice or fatigue effects. This enhances the validity of the results.

Question 28

What are the limitations of the matched pairs experimental design?

Answer 28

MATCHING IS NOT PERFECT: matching is time-consuming and can’t control all relevant variables. May not address participant variables.
MORE PARTICIPANTS: need twice as many participants as repeated measures for same data. More time spent recruiting which is expensive.