Types of experiment

• What is a laboratory experiment?

  Conducted in a controlled environment
• What does the researcher manipulate in a laboratory experiment?

  The independent variable (IV)
• What is a strength of laboratory experiments?

  High internal validity (cause and effect)
• What is a limitation of laboratory experiments?

  Low ecological validity (artificial setting)
• What is a field experiment?

  Conducted in a natural environment
• What is manipulated in a field experiment?

  The independent variable (IV)
• What is a strength of field experiments?

  Higher ecological validity than lab experiments
• What is a limitation of field experiments?

  Less control over extraneous variables
• What is a natural experiment?

  IV occurs naturally, not manipulated
• When are natural experiments often used?

  When manipulation is unethical or impractical
• What is a strength of natural experiments?

  Allows study of real-world issues
• What is a limitation of natural experiments?

  No control over the IV
• What is a quasi-experiment?

  IV based on pre-existing differences
• What is a strength of quasi-experiments?

  Allows comparisons between naturally occurring groups
• What is a limitation of quasi-experiments?

  No control over participant variables
• Why is random allocation not used in quasi-experiments?

  Because of pre-existing differences
• What are the types of experiments and their characteristics?

  1. Laboratory Experiment:

  • Controlled environment
  • High internal validity
  • Low ecological validity

  
  

  1. Field Experiment:

  • Natural environment
  • Higher ecological validity
  • Less control over variables

  
  

  1. Natural Experiment:

  • IV occurs naturally
  • Useful for ethical constraints
  • No control over IV

  
  

  1. Quasi-Experiment:

  • Based on pre-existing differences
  • No random allocation
  • Allows group comparisons