7.1.3.2 Repeated Measures

• Why do researchers use Repeated Measures Designs?

  To compare each person's results under different circumstances
• What are the key aspects of Repeated Measures Designs?

  • Participants: Same group used in all conditions
  • Conditions: Each participant experiences all conditions
  • Data Comparison: Compares within-person results across conditions
• How can you test memory using a Repeated Measures Design?

  By comparing recall with and without background music
• What is the advantage of using the same participants in all conditions of a Repeated Measures Design?

  It controls for individual differences in results
• Why are order effects a concern in repeated measures designs?

  They can confound the results of the study
• How can researchers mitigate the impact of order effects in repeated measures designs?

  By counterbalancing the order of tasks
• What is a repeated measures design?

  A design comparing different conditions in the same group
• How does Repeated Measures design control for individual differences?

  By using the same participants in all conditions
• How many participants are required in Repeated Measures Designs compared to other designs?

  Fewer participants are required
• What is a potential drawback of using Independent Measures design?

  Increased participant variability
• In the context of the background music study, what does Independent Measures involve?

  Two different groups taking exams
• What is a key advantage of Independent Measures design?

  No order effects are present
• What type of effects are present in Repeated Measures design?

  Order effects
• What is the fatigue effect in repeated measures designs?

  Tiredness from earlier tasks decreases performance
• What are the key differences between the control and treated groups over time?

  • At baseline, the signals are similar between groups
  • After injection, the treated group has a much higher signal than the control group
  • The signal in the treated group peaks around 1 hour after injection and then decreases over time
  • The control group signal remains relatively flat over time
• What does the graph show the relationship between?

  Signal and time for control and treated groups
• How can you test the effect of caffeine on test-taking performance using repeated measures design?

  Have students take tests with and without caffeine
• How could you use this data to determine the optimal time to measure the signal after treatment?

  • The data suggests the peak signal occurs around 1 hour after treatment
  • To capture the maximum effect, the optimal time to measure the signal would be around 1 hour after treatment
• What is a key advantage of Repeated Measures Designs?

  They eliminate participant variables
• Why are Repeated Measures Designs useful in these studies?

  They allow effective comparison of treatments while minimizing the impact of individual differences among participants
• What is a key consideration when using repeated measures designs?

  Conditions must not significantly affect future tasks
• What is the practice effect in repeated measures designs?

  Improvement due to prior experience, not treatment
• What are the disadvantages of repeated measures designs?

  • Order Effects:
  • Practice effect: Improvement due to prior experience
  • Fatigue effect: Decreased performance from tiredness
  • Demand Characteristics:
  • Participants guess study's purpose and alter behavior
• What are the appropriate conditions for using repeated measures designs?

  • Compare different conditions using the same group
  • Reduce variability caused by participant differences
  • Limited number of participants available
  • Conditions must be easily comparable
  • Conditions should not affect future tasks significantly
• How does repeated measures design help avoid participant variability?

  By comparing each participant's responses across conditions
• What is a disadvantage of repeated measures designs?

  Order effects
• When should you use repeated measures designs?

  When you have a limited number of participants
• Why are repeated measures designs ideal for comparing conditions?

  They reduce variability among participants' differences
• What are the potential limitations or drawbacks of using a Repeated Measures Design?

  • Potential for carryover effects if there is not enough time between treatments
  • Participant fatigue or practice effects if the number of conditions is too high
  • Increased complexity in the experimental design and data analysis
• What is a key ethical consideration in repeated measures designs?

  Informed consent
• What are the key components of a Repeated Measures Design?

  • Participants experience multiple conditions or treatments
  • Data is collected for each participant in each condition
  • Allows comparison of treatments while controlling for individual differences
• What should be explained to participants regarding informed consent?

  All study aspects, including conditions and withdrawal rights
• How does the number of participants differ between Repeated Measures and Independent Measures designs?

  Repeated Measures needs fewer participants
• How do Repeated Measures Designs help manage potential confounding factors?

  • Counterbalancing the order of conditions helps avoid order effects
  • Allowing adequate time between treatments helps avoid carryover effects
  • Comparing each participant's performance across conditions controls for individual differences
• What are the key components of analyzing data in repeated measures designs?

  • Compare results across conditions for each participant
  • Analyze "Treated" vs "Control" signals
  • Use baseline as a reference point
  • Address participant variability
• What type of effects are absent in Independent Measures design?

  Order effects
• How can order effects be minimized in repeated measures research?

  By using counterbalancing or randomization
• What impact do order effects have on performance in repeated measures designs?

  They can either improve or decrease performance
• What does the baseline represent in the analysis of repeated measures designs?

  The starting point for comparing signals over time
• What is the practice effect in Repeated Measures Design?

  Participants improve due to familiarity