CHAPTER 11 SingleSubject Small N Designs Lecture Outline

CHAPTER 11 Single-Subject / Small N Designs Lecture Outline The Beginnings of Psychology Research Reasons for Small N Designs Applied Behavior Analysis (ABA) Case Study Designs

THE BEGINNINGS OF PSYCHOLOGY RESEARCH Most early research in Psychology… • Small N • Data not summarized; data for each subject presented • Additional subjects used for replication • Dresslar’s facial vision study (1892) • falsification thinking

REASONS FOR SMALL N DESIGNS Misleading results from statistical summaries of grouped data • • A failure of individual-subject validity (e. g. discrimination learning research in children) Grouped data suggested gradual learning Individual data suggested hypothesis testing and quick solutions once proper hypothesis found Solution: children reach criterion at different rates Practical problems with large N designs • Participants with a particular attribute are rare • E. g. OCD occurs in <2% of the population • Members of a specific animal species are rare, costly, or require too much time for training Continuity theory Non-continuity theory

THE EXPERIMENTAL ANALYSIS OF BEHAVIOR Operant Conditioning • Behavior conditioned in a particular environment by consequences (e. g. reinforcement) • Primary DV rate of response • Recorded cumulatively

THE EXPERIMENTAL ANALYSIS OF BEHAVIOR Applied Behavior Analysis • Contemplative (understanding basic causes of events) vs. technological ideal (using science for control) • • Skinner using science to achieve control The issue of control • • • Comparing Watson and Skinner Attempt to control society Use of punishment for controlling selfdestructive behaviors Justified? E. g. Judge Rotenberg Center, Canton, MA

SMALL N DESIGNS IN APPLIED BEHAVIOR ANALYSIS A-B Design A-B-A Design Elements of Single-Subject Designs • • Importance of operational definitions (again); what constitutes a child’s problematic behavior? Baselines established Introduce some treatment Simplest format: A – B design A = baseline B = treatment A-B-A-B Design Withdrawal Designs • A-B-A – – • Treatment (B) introduced, then withdrawn To see if behavior change correlates with treatment change A-B-A-B – – Treatment (B) evaluated twice Experiment ends with treatment in place

SMALL N DESIGNS IN APPLIED BEHAVIOR ANALYSIS A-B-A-B Design • Research Example: Differential Reinforcement of Alternative Behavior (DRA) • Peer-mediated reinforcement of on-task behaviors for ADHD children External validity issue: laboratory study may not generalize to classroom •

SMALL N DESIGNS IN APPLIED BEHAVIOR ANALYSIS Multiple-Baseline Designs • Three varieties • • • One behavior, two or more subjects Two or more behaviors, one subject Two or more environments, one behavior, one subject

SMALL N DESIGNS IN APPLIED BEHAVIOR ANALYSIS Changing criterion designs • For behaviors that must be changed gradually • Operant principle of shaping

SMALL N DESIGNS IN APPLIED BEHAVIOR ANALYSIS Alternating treatments design • Compares relative effectiveness of two or more treatments

SMALL N DESIGNS IN APPLIED BEHAVIOR ANALYSIS 01 • • • Evaluating single-subject designs External validity issues Visual inspection instead of statistical analysis, although this is changing Hard to test interaction effects; effect on one type of person but not another?

CASE STUDY DESIGNS Survey Research Case study • • A detailed analysis of single individual or event Incorporates other methods (e. g. observation, psychometric tests) • Individual (both clinical and non-clinical cases) • • Effects of head trauma in a boxer The mind of a mnemonist Autistic savants Event • Response to catastrophic event

CASE STUDY DESIGNS Survey Research Evaluating case studies • Level of detail not found elsewhere • Can serve falsification (Remember Hans? ) • Limited control • External validity issues • Faulty memory problems