Experimental methods

Question 1

Types of experimental methods?

Answer 1

• Lab
• Field
• Natural
• Quasi

Question 2

Lab experiment

Answer 2

• Carried out in a controlled environment
• IV is manipulated
• EV is controlled
• Cause and effect relationships are established

Question 3

Independent variable

Answer 3

The variable that is manipulated in an experiment

Question 4

Dependent variable

Answer 4

Something that is measured following manipulation of the IV

Question 5

Operationalization of variables

Answer 5

How variables are defined and measured

Question 6

Extraneous variables

Answer 6

An unwanted variable that adds error to an experiment

Question 7

How is controlled achieved?

Answer 7

EV is held constant, changes in the DV only due to manipulation of the IV.
- Need a control group + experimental groups

Question 8

Randomization

Answer 8

• Ppts randomly allocated

- No extraneous influence = no influence on DV.

Question 9

Three features of lab experiments

Answer 9

• Direct manipulation of an IV
• Control
• Randomization

Question 10

Field experiment

Answer 10

• Takes place outside a lab environment
• IV is manipulated
• Cause and effect relationships can be inferred (concluded)

Question 11

Method of field experiment

Answer 11

• Measure natural behaviour

- Ppts often unaware = DV is behaviour of ppts.

Question 12

Natural experiment

Answer 12

• Naturally occurring changes in IV are observed
• IV unplanned
• Practical and ethical reasons = no control over variables + no manipulation of IV.
• Difficult to pinpoint a cause and effect relationship due to particular variables.

Question 13

Quasi-experiment

Answer 13

Ppts can’t be randomly assigned to experimental and control groups.
- Comparison condition

Question 14

The difference between natural and Quasi?

Answer 14

• Regarding the extent to which there is planned manipulation of the IV - not possible in natural.

Question 15

Strengths of the Lab experiment? 3 marks

Answer 15

• High levels of control of EV
• A high degree of replicability
• Cause and effect relationships can be uncovered

Question 16

Limitations of the Lab experiment? 3 marks

Answer 16

• Reduced ecological validity
• Increased risk of investigator effects and demand characteristics
• Ppts often required to behave in artificial ways

Question 17

Strengths of field experiment? 3 marks

Answer 17

• Cause and effect relationships can be uncovered
• Higher levels of ecological validity than a lab experiment
• Reduction in demand characteristics

Question 18

Limitations of field experiment? 2 marks

Answer 18

• Reduced control over EV

- Often more time consuming

Question 19

Strengths of natural and quasi-experiment? 2 marks

Answer 19

• Useful where it would be impractical or impossible to manipulate variables
• High levels of ecological validity

Question 20

Limitation of natural and quasi-experiment? 1 mark

Answer 20

• Not always possible to clearly identify cause and effect relationships