Experimental methods

• Lab

  > An experiment conducted in a lab which is a highly controlled environment

  > Where the researcher manipulates the IV and measures the effect on the DV
• Lab experiment AO3

  :) High control over extraneous variables, therefore cause and effect can be established

  :) High in reliability as it can easily be repeated

  :( Lacks ecological validity as it has been carried out in an artificial environment

  :( Prone to demand characteristics - help or hinder the researcher
• Field experiment

  > An experiment which takes place in a natural environment such as an office or school

  > Where the researcher manipulates the IV and measures the effect on the DV
• Field experiment AO3

  :) Less prone to demand characteristics as people may not know they are being watched

  :) High in ecological validity

  :( Low in reliability as the environment is natural

  :( This could create an ethical issue of lack of informed consent as people may not be aware they are being studied
• Natural experiment

  > The researcher takes advantage of a naturally occurring IV

  > This is a natural experiment because the variable would have changed even if the experimenter was not interested
• Natural experiment AO3

  :) Provide opportunities for research that may not have been undertaken for practical or ethical reasons eg rutters Romanian orphans

  :) High ecological validity as they are based on real life settings

  :( Naturally occurring event so lacks reliability as it is unlikely it will be able to be repeated

  :( Low control over extraneous variables
• Quasi experiment

  > An experiment which has an IV based on an existing individual difference between people

  > Which the researcher has not manipulated eg age or gender

  > The researcher measures the effect on the DV
• Quasi experiment AO3

  :( Sample bias as the sample being studied may have unique characteristics