Experimental Design + Types

• What are the different experimental designs?

  Independent groups, Repeated measures, Matched Pairs
• What is meant by independent groups?

  separate groups of participants in each condition
• What is meant by repeated measures?

  all participants experience all the conditions
• What is meant by matched pairs?

  take all participants and pair them on a variable relevant to the experiment
• What is meant by order effects?

  umbrella term used to group the boredom effect and the practice effect
• What is meant by the boredom effect in order effects?

  Decreased performance as the participant gets bored of repeating experiment in different conditions
• What is meant by practice effect in order effects?

  Improved performance due to repeating experiment in different conditions
• What are the pros of independent groups?

  1. no order effects
  2. reduced chance of demand characteristics
  3. cheaper than matched pairs
  4. quicker than repeated measures
• What are the cons of independent groups?

  1. participant variables have significant impact
  2. more expensive than repeated measures (need twice as many participants)
• Which experimental design is the most expensive and why?

  matched pairs because it is time consuming, and you have to pay for people's time
• Which experimental design is the quickest?

  independent groups
• Which experimental design is the slowest?

  matched pairs
• What are the pros of repeated measures?

  1. cheapest -> need fewer participants
  2. participant variables are not an issue
• What are the cons of repeated measures?

  1. order effects
  2. higher chance of demand characteristics
• What are the pros of matched pairs?

  1. no order effects
  2. reduce participant variables
  3. less chance of demand characteristics
• What are the cons of matched pairs?

  1. more expensive + time consuming
  2. may not be able to use everyone because you can't match them
• What is random allocation?

  process of assigning participants to different conditions randomly
• What is counter balancing?

  half the participants complete conditions in one order, other half of participants complete conditions in opposite order
• What are the types of experiment?

  Lab, Field, Natural, Quasi
• What is meant by a true experiment?

  IV is directly controlled
• Is a lab experiment a true experiment?

  yes
• Is a field experiment a true experiment?

  yes
• Is a natural experiment a true experiment?

  no
• Is a quasi experiment a true experiment?

  no
• Is random allocation possible in a lab experiment?


  yes
• Is random allocation possible in a field experiment?


  yes
• Is random allocation possible in a natural experiment?


  no
• Is random allocation possible in a quasi experiment?


  no
• What is meant by a laboratory study?

  experiment takes place in a controlled environment such as a lab
• What is meant by a field study?

  experiment takes place in a real world setting
• What is meant by a natural experiment?

  Research study using naturally occurring events like case studies
• What is meant by a quasi experiment?

  research study using a naturally occurring difference between people (e.g. gambling addiction)
• What are the pros of a lab experiment?

  1. high level of control -> high internal validity
  2. causal relationship
  3. replication possible -> reliable
• What is meant by a causal relationship?

  a change in IV caused the change in DV
• What are the pros of a field experiment?

  1. some causal relationship -> harder to establish -> less control
  2. high ecological validity
  3. low chance of demand characteristics
• What are the pros of a natural experiment?

  1. ethics -> can study a variable that would not be ethical to replicate
  2. high ecological validity
• What are the pros of a quasi experiment?

  OFTEN but not always:

  1. control
  2. ecological validity
  3. ethics -> likely to know they're in a study so informed consent
• What are the cons of a lab experiment?

  1. artificial setting + task -> lacks mundane realism
  2. chance of demand characteristics
  3. experimenter bias
  4. ethics -> deception used to reduce demand characteristics
• What are the cons of a field experiment?

  1. less control than lab
  2. harder to replicate
  3. ethics -> may not know they're in a study -> lack of informed consent
• What are the cons of a natural experiment?

  1. harder to establish causal relationship
  2. rarity
  3. demand characteristics
  4. experimenter bias