Types of experiment

• Describe a laboratory experiment


  An experiment carried out in a controlled/artifical experiment.

  The IV is directly minipulated

  PPS can randomly be allocated to conditions
• What are the strenghts of a laboratory experiment?


  High control, Easily replicated and cause and effect can be established.
• What are the weaknesses of a laboratory experiment?


  Ecological validity and demand characteristics are a huge issue and effects the validity.
• What are examples of a laboratory experiment?

  Asch and Milgram
• Describe a field experiment


  Carried out in a natural enviroment, IV is manipulated and PPS can randomly be allocated to conditions.
• What are the strengths of a field experiment?


  High ecological validity and reduced demand characteristics.
• What are the weaknesses of a field experiment?


  No control over confounding variables

  Cause and effect is harder to establish

  Replication is an issue

  Ethics such as infromed concent and deception is an issue
• Give examples of a field experiment?


  Hofling and Bickman
• Describe a natural experiment?


  IV is not manipulated (naturally occuring) and makes use of pre-existing IV.
• What are the strenghts of a natural experiment?


  High ecological validity, No demand characteristics and ethics are not a risk.
• What are the weaknesses of a natural experiment?


  No control of confounding varibles

  Cause and effect is harder to establish

  Replication is impossible

  Random allocation is impossible
• What are examples of a natural experiment?


  Sperry and Rutter
• What is the description of a Quasi experiment?


  Investigates affect on IV and DV

  Makes use of an IV that no one has to interfere with (biological)
• What are the strenghts of a Quasi experiment?


  High ecological validity, no demand characteristics and ethics are not at risk.
• What are the weaknesses of a Quasi experiment?


  No control of confounding variables, cause and effect is harder to establish, replication is impossible, random allocation is impossible.