types of experiments Flashcards
What are four types of experiments?
- Laboratory
- Field
- Natural
- Quasi
What is a laboratory experiment?
- Controlled environment
- Extraneous and confounding variable regulated
- Participants go to researchers
- IV manipulated
– DV recorded
What do experiments allow us to do?
-Study causation (cause and effect)
What are the 3 key features of a true experiment?
- Manipulation of an independent variable (IV)
- Randomisation of participants to conditions
- Control of extraneous variables
Strengths of Laboratory Experiment:
Extraneous/confounding variables controlled = high internal validity
-Easily replicated = standardised
Limitations of Laboratory Experiment:
Lack generalisabilty = artificial setting
Low external validity (ecological validity + mundane realism)
Demand characteristics
Investigator effect
What is a field experiment?
Natural environment
Research goes to participant
IV manipulated
DV recorded
Strengths of Field Experiment:
More natural environment = high ecological validity
Reduced demand characteristics
Causation
Limitations of Field Experiment:
Less control of extraneous variables = difficult to repeat
Ethical concerns = informed consent
More time consuming
What is a natural experiment?
- No manipulation of IV
- DV may be naturally occurring or measured by experimenter
Strengths of Natural Experiment:
- Only ethical option
- High ecological validity
Limitations of Natural Experiment:
- Confounding variable = participants already in conditions
- NOT randomly allocated
- Difficult to replicate (may be one-off)
What is a quasi experiment?
- Pre-existing difference people
- Naturally or measured DV
Strengths of a Quasi-Experiment:
High control = increase confidence of causation
Comparison between different types of people
Useful where it would be unethical to manipulate IV
Limitations of a Quasi-Experiment:
Not randomly allocated = participant variables
Difficult to replicate
Causal relationship not demonstrated
