experiments

what are the four types of experiments

1. lab

2. field

3. natural

4. quasi

explain lab experiments

IV = manipulated by researcher
environment = highly controlled

strength of lab experiment

more control over extraneous variables so replication is more possible

high internal reliability and validity

weakness of lab experiment

may lack generalisability as pps may display unnatural behaviour therefore low external validity

low ecological validity

explain field experiment

IV= manipulated by researcher

environment = natural

strengths of field experiment

high mundane realism, greater ecological validity, less chance of demand characteristics

explain natural experiment

IV = naturally occurring

environment = natural

strength of natural experiment

no demand characteristics
high external validity
allows opportunity for research that would otherwise not be possible

weakness of natural

opportunity to conduct research is rare

poor control of extraneous variables

explain quasi experiment

IV = natural/ pre-existing (dispositional)

environment = either controlled or natural

strengths of quasi

mostly common in control so share strengths with lab experiments

weaknesses of quasi

no random allocation possible so could lead to extraneous variables

what are the three types of experimental design

1. independent groups

2. repeated measures

3. matched pairs

what is independent groups

pps are divided into 2 groups
one group does 1st condition other group does 2nd condition

what is the strengths of independent groups

not affected by order affects

not affected by demand characteristics

weaknesses of independent groups

differences between pps can act as extraneous variables