Types of Experiment Flashcards
What is a laboratory experiment
conducted in a deliberately constructed and controlled environment where the IV is set up and changed by the researcher
Strengths of a laboratory experiment
- control leads to confidence in cause and effect relationship
- high internal validity since observed effect is due to the independent variable
- highly replicable
Limitations of a laboratory experiment
- lack external (ecological) validity due to such high control meaning not generalisable to real life behaviour
- tasks lack mundane realism
- participants are well aware they are in an experiment so suffers demand characteristics
What is a field experiment
Conducted in a real life setting for the behaviour of study and the researcher manipulates the IV
Strengths of a field experiment
- increased external (ecological) validity as natural setting means findings can be generalised to real life behaviour
- tasks are more likely to be normal so increased mundane realism
- if participants unaware then no demand characteristics
Limitations of a field experiment
- real world setting so cannot control everything therefore more extraneous variables
- difficult to assign participants to groups therefore the change in the dependent variable may be due to participant variables reducing the internal validity
- less easy to replicate to check reliability
- ethical issues if participants don’t know they are being studied
What is a natural experiment
Levels of independent variable have happened naturally, the researcher just measures the change in the dependent variable between the two conditions
Strengths of a natural experiment
- allows research into areas that couldn’t be done otherwise due to cost or ethics
- high in external validity as this is real behaviour occurring in the real world so there is little risk of demand characteristics
Limitations of a natural experiment
- researcher has no control over the experiment so extraneous variables are not controlled so it’s harder to establish a cause and effect relationship
- the studies are often rare so cannot be replicated to check reliability
- participants are not randomly allocated to conditions which is a threat to internal validity
What is a quasi experiment
takes place in a laboratory or real life setting but participants are automatically assigned to a particular condition due to a characteristic they have
Strengths of a quasi experiment
- less experimenter bias in participant condition allocation as it isn’t done by the researcher
Limitations of a quasi experiment
- there may be a difference in the group that goes beyond group membership - confounding variables
- participants may be aware of the study leading to demand characteristics
- more chance of participant variables as they are not randomly allocated to a condition
