Types of experiment Flashcards
Define the term laboratory experiment.
An experiment conducted in a highly controlled environment. The IV is manipulated to see the impact on the DV, whilst the effects of other variables are minimised as far as possible. For example, giving researchers lists of words to remember, giving them another task to prevent rehearsal, then testing their recall of the information.
What are the strengths of lab experiments?
High control over confounding and extraneous variables - ensure the effect on dependent variable is the result of the manipulation of the independent variable thus more certain of causation (high internal validity).
Replicable as there will be a controlled, standardised procedure, increasing the reliability of the results.
What are limitations of lab experiments?
Artificial nature of the set-up means that the results may not reflect ‘real-life’ behaviour, so reducing the external validity of the study.
Tasks given in the research may not be reflective of everyday tasks (lack of mundane realism).
Participants know they are being tested so may change their behaviour (demand characteristics).
Define the term field experiment.
An experiment where the independent variable is manipulated in a natural, more everyday setting. The researcher goes to the participants’ usual environment. For example, Piliavin (1969) got a confederate to carrying a walking stick to see how many people helped in each condition.
What are the strengths of field experiments?
Have higher mundane realism than lab experiments because the environment is more natural - producing behaviour that’s more valid and authentic especially the case as participants may be unaware that they are being studied (high external validity).
What are the limitations of field experiments?
Harder to control extraneous variables, so harder to know if the IV has affected the DV.
Not often possible to replicate.
If participants are unaware they are being studied this raises ethical issues (lack of informed consent).
Define the term natural experiment.
An experiment where the change in IV isn’t brought about by the researcher but would have happened even if the researcher wasn’t there. The researcher records the effect on the DV they have decided on.
What are the strengths of natural experiments?
Provides opportunities for research that may not be undertaken for practical or ethical reasons, such as the studies of institutionalised Romanian orphans (Rutter et al.
Have high external validity because they involve the study of real-world issues and problems as they happen.
What are the limitations of natural experiments?
Even less control over extraneous variable than field experiments.
Participants can’t be randomly allocated to conditions, introducing the possibility of bias.
Naturally occurring IVs may be rare, so studies can’t be repeated.
Define the term quasi-experiment.
A study where the IV is based on an existing difference between people. For example, gender differences in attitudes towards food.
What are the strengths of quasi-experiments?
Carried out under controlled conditions - share strengths of lab experiment (e.g., replicable).
High control over confounding and extraneous variables - ensure the effect on dependent variable is the result of the manipulation of the independent variable thus more certain of causation (high internal validity).
Replicable as there will be a controlled, standardised procedure, increasing the reliability of the results.
What are the limitations of quasi-experiments?
Like natural experiments can’t randomly allocate participants introducing possible confounding variables.
