Experimental methods & designs Flashcards
What are the four types of experimental methods?
Lab, field, natural and quasi
Lab experiment
It is conducted in a controlled environment where variables can be manipulated.
Strengths and weaknesses of lab experiments
strengths
- More replicable
- Extraneous variables
minimised
- High levels of internal reliability
weaknesses
- Lack ecological validity
- Increases likelihood of demand
characteristics.
Field experiment
It is conducted in real life settings e.g. school, workplace etc.
Field experiment evaluation
Strengths
- High ecological validity
- Less likely to have demand
characteristics
Weaknesses
- Harder to replicate
- Harder to control extraneous
variables
Natural experiment
A study that occurs naturally or is outside the control of the researcher.
Natural experiment evaluation
Strengths
- High external validity
(ecological)
Weaknesses
- Rare opportunity ( hard to
replicate)
- Often confounding variables
Quasi experiment
A study where the researchers can’t directly manipulate the IV
Quasi experiment evaluation
Strengths
- High ecological validity
Weaknesses
- Often confounding variables
What are the three types of experimental designs?
Repeated measures, independent measures and matched pairs
Repeated measures
It involves testing the same group of participants across all of the conditions. Their scores are compared in condition one and 2 which means they serve as their own control.
Repeated measures evaluation
Strengths
- No order effects
- Less demand characteristics
Weaknesses
- Need more participants
- may be participant variables
Independent measures
Involves assigning different groups of participants to different experimental conditions. Participants only take part in one condition.
Independent measures evaluation
Strengths
- Participant variables controlled
Weaknesses
- Demand characteristics
Matched pairs
This involves matches participants based on relevant characteristics and then randomly assigning them to different conditions.
