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Reianna Shakil L6EFPsychology22/09/12
Strengths and weaknesses of experimental methods
Laboratory experiment: Artificial environment with tight controls over variables.
Tighter control of variables. Easier to Demand characteristics - participants aware
comment on cause and effect. of experiment, may change behaviour.
Relatively easy to replicate. Artificial environment low mundane
Enable use of complex equipment. May have low ecological validity - difficult to
generalise to other situations.
Often cheaper and less Experimenter effects - bias when
time-consuming than other methods. experimenter's expectations affect
Field experiment: Natural environment with independent variable manipulated by
People may behave more naturally than in Often only weak control of extraneous
laboratory - higher mundane realism. variables - difficult to replicate.
Easier to generalise from results. Can be time-consuming and costly.
Natural experiment: Natural changes in independent variable are used - it is not
Situations in which it would be ethically The independent variable is not controlled by
unacceptable to manipulate the independent the experimenter.
Less chance of demand characteristics or No control over the allocation of
experimenter bias interfering. participants to groups (random in a 'true
Note: In a true experiment participants are randomly allocated to groups.