Lesson 3 (expepsych)

• Within-Subjects Design


  Also called as repeated-measures design where subjects are assigned to more than one treatment condition
• Within-Subjects Factorial Design


  A factorial design in which subjects receive all conditions in the experiment
• Practical Limitations of Within-Subjects Design


  • Progressive Error
  • Fatigue Effects
  • Practice Effects
  • Order Effects
• Counterbalancing


  • Subject-by-Subject Counterbalancing
  • Across Subject Counterbalancing
• Subject-by-Subject Counterbalancing


  A technique for controlling progressive error for each individual subject by presenting all treatment conditions more than once
• Subject-by-Subject Counterbalancing Techniques


  • Reverse Counterbalancing
  • Block Randomization
• Across-Subject Counterbalancing


  They are used to distribute the effects of progressive error so that if we average across subjects, the effects will be the same for all conditions of the experiment
• Across-Subject Counterbalancing Techniques


  • Complete Counterbalancing
  • Partial Counterbalancing
• Choosing Among Counterbalancing Procedures


  If we expect larger differences in the pattern of progressive error each subject-Use subject-by-subject counterbalancing

  If we know the effects will be the same for everyone, Use across-subject-counterbalancing
• Baseline


  A measure of behavior as it normally occurs without experimental manipulation
• ABA Designs


  A (the baseline condition) comes first, followed by B the (experimental condition), finally, we return to the baseline condition (A) to verify that the change in behavior is linked to the independent variable
• Multiple Baseline Designs


  • Assess the effects of a treatment across subjects

  Assess the effects of a treatment across behaviors

  Multiple baseline of the same behavior of one subject across different settings
• Counterbalancing procedures


  • Every experiment under within-subjects design needs some form of counterbalancing
  • If we expect larger differences in the pattern of progressive error each subject-Use subject-by-subject counterbalancing
  • If we know the effects will be the same for everyone, Use across-subject-counterbalancing
• ABA design


  A (the baseline condition) comes first, followed by B the (experimental condition), Finally, we return to the baseline condition (A) to verify that the change in behavior is linked to the independent variable
• Multiple baseline designs


  • Assess the effects of a treatment across subjects
  • Assess the effects of a treatment across behaviors
  • Multiple baseline of the same behavior of one subject across different settings
• Changing criterion design

  An initial baseline phase is followed by implementation of a treatment program delivered in a series of phases, Each phase has its own criterion rate for the target behavior, and once responding becomes stable an incremental shift in the criterion occurs to implement another phase
• Discrete trial design


  A single cycle of instruction that may be repeated several times until a skill is mastered, A discrete trials design has no baselines and administers the levels of the independent variable 100s to 1000s of times to each subject