Research Methods: Experiments

Question 1

Define Experiments.
What can we show by manipulating the IV and measuring the DV?

Answer 1

The comparison of two conditions of the IV.
Cause and effect

Question 2

What is the independent variable (IV)?

Answer 2

The variable that the researcher wants to test to see if it affects the outcome being measured.

Question 3

What is the dependent variable (DV)?

Answer 3

The variable the researcher does not control or manipulate - it is simply recorded.

Question 4

The DV provides data. What are three ways data can be measured?

Answer 4

A questionnaire, an observation, and a reading of a biological factor e.g. heart rate

Question 5

What is an extraneous variable (EV)?

Answer 5

Anything that might possibly interfere with the experiment, a ‘nuisance’. E.g. noise, temperature, busy-ness of street, things that may vary in participants, etc.

Question 6

Define Control.

Answer 6

Keeping things the same so they don’t interfere.

Question 7

What is a confounding variable (CV)?

Answer 7

Something which, if you didn’t control would influence the results. It is said to ‘vary with the IV’ - it is different in each condition and therefore acts like another IV. E.g. driving experience

Question 8

Define Operationalise.

Answer 8

To specify behaviors that can be measured or manipulated. - always be as specific as possible. Operationalising applies to both the IV and DV.

Question 9

Define Hypothesis.

Answer 9

A clear precise testable statement stating the relationship between the variables to be investigated. Stated at the outset of any experiment or correlational study.

Question 10

What do experimental hypotheses always predict?

Answer 10

That there will be a difference between the two conditions of the IV (on whatever is being measured).

Question 11

Define Non-directional Hypothesis.
When is it used?

Answer 11

The direction of results is not predicted. Used when no previous research in the area. (Say that groups will differ)

Question 12

Define Directional Hypothesis.
When is it used?

Answer 12

Predict the expected direction of the results. Only used if previous research shows the likely outcome. (Say that one group will be e.g. higher, faster, etc.)

Question 13

Define Null Hypothesis.

Answer 13

This is the statement that there will not be a difference (just add no/not to your hypothesis).

Question 14

Define Participant Variables.

Answer 14

Anything that may vary between participants which may affect the DV.

Question 15

Define Situational Variables.

Answer 15

Anything in the research situation that may affect the DV.

Question 16

What are some examples of Participant Variables?

Answer 16

Gender, ethnicity, IQ, mental health, past experiences, attention span, personality factors, wealth/socioeconomic status, parenthood and disability

Question 17

Define Experimental Designs.

Answer 17

The 3 ways to carry out the experiment with participants. Each design controls for participant variables in some way.

Question 18

What are the 3 Experimental Designs?

Answer 18

1. Independent Groups Design
2. Repeated Measures Design
3. Matched Pairs Design

Question 19

Describe the Independent Groups Design.

Answer 19

Using different participants for each condition. Participants only take part in one condition. Randomly allocating participants to groups controls participant variables to some extent.

Question 20

Describe the Repeated Measures Design.

Answer 20

Using the same participants for each condition of the experiment. Participants take part in both conditions. This represents perfect control of participant variables as every participant appears in both groups.

Question 21

Describe the Matched Pairs Design.

Answer 21

Using different participants but matched for each condition. Participants take part in one condition. Matched on similar characteristics that may affect the DV. You can control for some participant variables which you believe to be particularly important.

Question 22

What are the strengths and weaknesses of the Independent Groups Design?

Answer 22

Strengths:
- no order effects (compared to repeated measures)
- less chance of demand characteristics (one condition only)

Weaknesses:
- participant variables (differ between participants)
- number of participants (need more - time + money consuming)

Question 23

What are the strengths and weaknesses of the Repeated Measures Design?

Answer 23

Strengths:
- participant variables (fully controlled so more valid)
- number of participants (fewer so quicker and cheaper)

Weaknesses:
- possible order effects
- more chance of demand characteristics

Question 24

What are the strengths and weaknesses of the Matched Pairs Design?

Answer 24

Strengths:
- no order effects (compared to repeated measures)
- last chance of demand characteristics (compared to repeated measures)
- participant variables (some are controlled)

Weaknesses:
- participant variables (some won’t be controlled)
- number of participants (more, and may be difficult to match them - more time + money consuming)

Question 25

What are some examples of Situational Variables?

Answer 25

Temp, noise, demand characteristics, investigator effects, order effects

Question 26

Define Demand Characteristics.

Answer 26

Participants being aware of what the aim or expected results are and what this implies for how participants are expected to behave (may change behaviour which affects validity of results)

Question 27

How can we control Demand Characteristics?

Answer 27

Deception - if participants are unaware of the aim of the study or what the conditions are then this is called a ‘single blind’ . OR, making sure participants only do one condition of the experiment.

Question 28

Define Investigator Effects.

Answer 28

Any behaviour of the researcher that may inadvertently affect the study including interaction with participants (conscious or unconscious) e.g. selection of participants, leading questions, etc.

Question 29

How can we control Investigator Effects?

Answer 29

Randomisation:
- randomly allocate participants to groups
- randomly assigned task A or task B first
- randomly order questions on a questionnaire

Can conduct a ‘double blind’ study where neither the participant nor the researcher conducting the tasks is aware of the aim or which condition the participant is in.

Question 30

Define Order Effects.

Answer 30

The order of the conditions affecting the participants’ behavior. They only occur in Repeated Measures Design. E.g. boredom, fatigue, practice, etc.

Question 31

How can we control Order Effects?

Answer 31

Counterbalancing - also known as ABBA. Half of each group of participants in a repeated measures design take part in C1 first, half take part in C2 first. They then do the other condition. This doesn’t remove order effects but it balances them out so they don’t affect results.

Question 32

What form of control is used for ALL designs?

Answer 32

Standardisation - all participants do the same test/task. They are given the same instructions. Prevents bias or differences in experience of participants from affecting results.