Types of experiments

• Types of experiments


  • Lab experiments
  • Field experiments
  • Natural experiments
  • Quasi experiments
• Lab experiments


  • Conducted in a controlled environment, IV is manipulated and DV is measured
  • Strengths: Precise control of variables, easier to replicate
  • Weaknesses: Artificial situations, lack of ecological validity
• Field experiments


  • Carried out in a real world setting, IV is manipulated by the experimenter
  • Strengths: Higher ecological validity, less demand characteristics
  • Weaknesses: Less control over extraneous variables, ethical issues
• Natural experiments


  • Conducted in a natural environment, researcher does not manipulate the IV
  • Strengths: High ecological validity, useful for unethical situations
  • Weaknesses: Many extraneous variables, cannot conclude cause and effect
• Quasi experiments


  • Have an IV based on an existing difference between people
  • Strengths: Precise control of extraneous variables, easier to replicate
  • Weaknesses: Higher risk of confounding variables
• Extraneous variables


  Any variable other than the IV that might have affected the DV
• Confounding variables


  Types of extraneous variables that are related to the IV, can act as another IV
• Experiments


  • Control the investigation as much as possible e.g. try to conduct lab experiments with standardised procedures, standardised instructions; environment kept as constant as possible
  • Operationalise variables
  • Pilot test – to identify any problems