Experimental Methods Flashcards
lab, field, natural, quasi
what is a laboratory experiment??
experiment that is conducted in a controlled environment of the researcher’s choice
advantages of a lab experiment
easy to replicate - due to the high degree of control, it is easy to test the reliability of the findings
high degree of control - extraneous variables are well controlled. it is easy to assume that changes in the DV are due to changes in the IV.
disadvantages of lab experiment
low ecological validity - hard to generalise the findings to real life situations, so it is artificial. we can’t assume that the ppts would react the same way
demand characteristics - ppts may change their behaviour to fit in with what they believe is what the experimenter wants/ doesn’t want
what is a field experiment??
conducted in the ppts natural environment. measuring behaviour in the location that it is naturally occurring
advantages of field experiment
high ecological validity - conducted in ppts own natural environment so we assume that they are acting like they normally would
less chance of demand characteristics - often unaware that they are taking part in a study so less likely to change their behaviour to fit into the experiment.
disadvantages of field experiment
less control - less control of extraneous variables. the cause and effect between the IV and DV is not as strong as in lab
potential ethical issues - ppts might not know they are taking part in the study, this is unethical as they may have not given consent to researchers prior to the study.
what is a natural experiment??
IV is naturally occurring. the researcher can’t directly change it. eg: age, eye colour, height
advantages of natural experiment
high ecological validity - IV is not manipulated at all by the researchers. ppts are acting as they would normally, it just happens that researchers are there to measure their behaviours.
allows the study of sensitive behaviours - often natural experiments involve an IV that would be unethical to manipulate.
disadvantages of natural experiment
difficult to replicate - changes in the IV are ‘one offs’ and so the reliability of the results can’t be tested through replication.
lack of control - IV is not directly manipulated by the researcher, there is less control in natural experiments than in lab
what is a quasi experiment??
IV forms a part of the ppts
eg: age, gender or personality types.
advantages of quasi experiment
high degree of control - often carried out in the same conditions as lab. easier to eliminate extraneous variables
replicable - don’t rely on ‘one off’ or rare situations occurring. when the IV is straight forward (age, gender) it is easier to repeat the study with a larger group to check the reliability of the findings.
disadvantages of quasi experiment
random allocation to conditions is not possible - the chance that the 2 conditions could differ on a variable that might affect the DV
difficult to find a sample if one condition of the IV is rare - some traits within participants are quite rare so can be hard to recruit the required number.
