Experimental methods Flashcards
Types of experimental methods?
- Lab
- Field
- Natural
- Quasi
Lab experiment
- Carried out in a controlled environment
- IV is manipulated
- EV is controlled
- Cause and effect relationships are established
Independent variable
The variable that is manipulated in an experiment
Dependent variable
Something that is measured following manipulation of the IV
Operationalization of variables
How variables are defined and measured
Extraneous variables
An unwanted variable that adds error to an experiment
How is controlled achieved?
EV is held constant, changes in the DV only due to manipulation of the IV.
- Need a control group + experimental groups
Randomization
- Ppts randomly allocated
- No extraneous influence = no influence on DV.
Three features of lab experiments
- Direct manipulation of an IV
- Control
- Randomization
Field experiment
- Takes place outside a lab environment
- IV is manipulated
- Cause and effect relationships can be inferred (concluded)
Method of field experiment
- Measure natural behaviour
- Ppts often unaware = DV is behaviour of ppts.
Natural experiment
- 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.
Quasi-experiment
Ppts can’t be randomly assigned to experimental and control groups.
- Comparison condition
The difference between natural and Quasi?
- Regarding the extent to which there is planned manipulation of the IV - not possible in natural.
Strengths of the Lab experiment? 3 marks
- High levels of control of EV
- A high degree of replicability
- Cause and effect relationships can be uncovered
