Experimental design

• What does experimental design refer to in psychology?

  How participants are allocated to conditions
• What are the three main types of experimental designs?

  1. Independent Groups Design
  2. Repeated Measures Design
  3. Matched Pairs Design
• What is an Independent Groups Design?

  Different participants in each condition
• What are the strengths and limitations of Independent Groups Design?

  Strengths:

  • No order effects (e.g. fatigue, practice)
  • Lower risk of demand characteristics

  
  

  Limitations:

  • Participant variables may affect results
  • Needs more participants
• What is a Repeated Measures Design?

  Same participants take part in all conditions
• What are the strengths and limitations of Repeated Measures Design?

  Strengths:

  • Controls for participant variables
  • Requires fewer participants

  
  

  Limitations:

  • Order effects (e.g. boredom, learning)
  • May increase demand characteristics
• How can order effects be reduced in Repeated Measures Design?

  By using counterbalancing
• What is the purpose of counterbalancing?

  To reduce order effects in experiments
• What is a Matched Pairs Design?

  Participants matched on key variables, then split
• What are the strengths and limitations of Matched Pairs Design?

  Strengths:

  • Controls for participant variables
  • No order effects

  
  

  Limitations:

  • Time-consuming to match participants
  • May not match perfectly