Types Of Experiment

• Laboratory experiments

  Conducted in a highly controlled environment
• Strengths of laboratory experiments

  High control over EVs so researcher is sure any effect on DV is from the manipulation of IV and thus, lab exp have high internal validity. Replication is made possible due to high levels of control and ensures no new EVs are present -helps check validity of exp
• Limitations of laboratory experiments

  Lacks generalisability as lab exps are artificial causing them to have low mundane realism and ecological validity and thus, ppts may act unusually due to unfamiliar context. Therefore, their behaviour can't be generalised- low external validity. Demand char as ppts know they're in a lab
• Field experiments


  The IV is manipulated in a natural, more everyday setting
• Strengths of field experiments

  Higher ecological validity and mundane realism as exp is more natural and thus, produces behaviour that is more valid and authentic. High external validity as ppts don't know they are being tested
• Limitations of field experiments

  Causality can not be established due to uncontrollable EVs and there are many CVs so low internal validity. Precise replication is not possible.Important ethical issues also with consent and invasion of privacy as ppts don't know they're in study
• Natural experiments

  When the researcher takes advantage of a pre-existing IV and it's called natural as IV would change even if researcher is not interested- could occur in a lab
• Strengths of natural experiments

  High external validity as it includes study of real-life issues and problems and thus, may have good practical applications in the real world. This provides opportunities that could not be undertaken otherwise due to practical/ethical issues
• Limitations to natural experiments

  Naturally occurring event may happen rarely so there is small opportunity for research and thus, may limit generalisability of findings. No random assignment of participants to conditions, so there are biases in the different groups of participants and causality cannot be established due to EVs
• Quasi experiments


  Have an IV based on an existing difference between people. No one manipulated the IV, it simply exists.
• Strengths of quasi experiments

  Allows study of an independent variable that cannot be manipulated and may well have good practical applications in the real world while it is under strictly controlled conditions
• limitations of quasi experiments

  No random assignment of participants to conditions, so there may be biases and CVs in the different group of participants.Causality cannot be established due to uncontrolled EVs