Experimental design

• What is the first step in running an experiment?

  Design a study
• What are the two conditions in the example experiment?

  • Condition 1: Drinking Speedup
  • Condition 2: Drinking water
• How many conditions do most simple experiments involve?

  Two conditions
• What is an independent groups design?

  Participants take part in one condition only
• What is a repeated measures design?

  Participants take part in both conditions
• What is a matched pairs design?

  Participants are matched on influencing characteristics
• What are order effects?

  Order of conditions affects participants' behavior
• What are the strengths of independent groups design?

  • No order effects
  • Less demand characteristics
  • Same test/stimulus material used
• What can cause performance improvement in the second condition?

  Practice effect
• What can cause performance decline in the second condition?

  Fatigue effect
• What are the limitations of independent groups design?

  • Participant variables may affect results
  • Less economical, needing more participants
• What are the strengths of repeated measures design?

  • No participant variables
  • More economical with fewer participants
• What are the limitations of repeated measures design?

  • Order effects can occur
  • Higher demand characteristics
• What is counterbalancing?

  Half do condition A first, half do B
• What is the purpose of counterbalancing?

  Control impact of order effects
• What are the strengths of matched pairs design?

  • Reduces order effects and demand characteristics
  • Same test/stimulus can be used
  • Participant variables are reduced
• What are the limitations of matched pairs design?

  • Time-consuming to match participants
  • Participant variables still exist
  • Less economical, needing more participants
• What is the activity mentioned at the end of the material?

  Which experimental design?
• What is the role of hypothesis in experimental design?

  Guides the study's focus and direction
• How does random allocation help in experiments?

  Reduces participant variables across conditions
• What are demand characteristics?

  Participants guess the aim and change behavior
• Why is it important to use the same test/stimulus material?

  Ensures consistency across conditions
• How do participant characteristics influence experimental outcomes?

  They can introduce variability in results
• What is the impact of fatigue effects in repeated measures design?

  Can lead to worse performance in second condition
• What is the impact of practice effects in repeated measures design?

  Can lead to better performance in second condition
• What is the necessity of pretests in matched pairs design?

  Helps to match participants on characteristics