Types of experiments

• What are the four diff types of experiments?

  • Laboratory experiments
  • Field experiments
  • Natural experiments
  • Quasi experiments
• What is a lab experiment?

  Experiment that takes place in a controlled environment where the researcher manipulates the IV, records the effect on the DV whilst maintaining control of extraneous variables
• Advantages of lab experiment

  • High control over confounding variables + extraneous variables - ensures high internal validity
  • Easy to replicate - increases validity of findings
• Disadvantages of lab experiments

  • Lack generalisability and low external validity - lab environment is artificial so in unfamiliar context, ppt may act in unusual ways so their behaviour cannot be generalised beyond the research setting
  • Risk of demand characteristics - ppts know they are being tested
  • Low mundane realism
• What are field experiments?

  An experiment that takes place in a natural, everyday setting
• Advantages of field experiments

  • Higher mundane realism - environment is more natural
  • Ppts are unaware they are being studied so behaviour is more authentic - high external validity
• Disadvantages of field experiments

  • Low control over extraneous variables - cause and effect between IV/DV more difficult to identify + close replication is unlikely
  • Ethical issues - ppts don't consent as they are unaware of study + invasion of privacy
• What are natural experiments?

  Experiment where the researcher has no control over the IV and researcher cannot change it (IV changes naturally) - something else causes it to change e.g. before and after a natural disaster
• Advantages of natural experiments

  • Provide opportunities for research that may not otherwise be undertaken for practical/ethical reasons
  • High external validity - involves study of real-world issues/problems
• Disadvantages of natural experiments

  • A natural occuring event may only happen very rarely, reducing opportunities for research - limits scope for generalisation to other similar situations
  • Ppts may not be randomly allocated so researcher is less sure whether the IV affected the DV
• What are quasi-experiments

  Experiments that have an IV that is based on an preexisting difference between people (e.g. age, gender) and unlike a natural experiment the IV cannot be changed
• Advantages of quasi-experiments

  • Controlled conditions
  • No demand characteristics
• Disadvantages of quasi

  • Cannot randomly allocate so their may be EV and confounding variables