Experimental Method (experiment types)

• what are the four types of experiments?

  • Laboratory
  • field
  • natural
  • quasi-experiment.
• what is a Lab Experiment?

  Controlled test in a scientific setting.
• strength of Lab experiments

  • has control over confounding and extraneous variables, so the effect on the dependent variable is only the independent variable being manipulated
  • establishes cause and effect, so it has high internal validity
  • easily replicated because it is highly controlled, replication helps an experiment be seen as valid
• limitation of Lab experiments

  • lacks generalisability (to the world) as the environment is artificial, so the behaviour would be seen as unusual in everyday life
• what is a field experiment?

  Research conducted in a real-world setting outside of a laboratory, where the IV is still manipulated
• strength of Field experiments

  • conducted in a natural environment/everyday setting, meaning that the behaviour is more authentic to everyday life, making the study more valid
  • this can be furthered when the participants dont know they are being observed (high external validity)
• limitation of Field experiments

  • ethical issues as participants cannot consent, especially if they dont know they are being observed, so it is an invasion of privacy
• what is a natural experiment?

  an experiment where there is no control over the independent variable as it is already occurring with the dependent variable

  -> the setting doesn't have to be natural as long as the independent variable is natural, so it can be conducted in a lab
• strengths of natural experiments?

  • high external validity
  • provides opportunities to research something that is unethical or impractical in other settings e.g. a natural disaster
• limitations of a Natural experiment

  • naturally occurring events are rare, so there is reduced opportunities
  • participants may not be randomly allocated to the experiment conditions
• what is a Quasi experiment?

  an experiment where the independent variable is naturally occurring in age or gender between the participants
• strengths of a quasi experiment

  • can mimic an experiment to provide high quality evidence without random allocation
  • serval designs can be applied
  • used when practical or ethical reasons why people can be randomised appear in the study
• limitations of a Quasi experiment

  • choosing comparison in experiment can be difficult
  • cannot rule out other factors/extraneous variables/control variables that affect/cause the result of your evaluation