Single-Case Research

1. Single-Case Research • Single-case research is idiographic rather than nomothetic. • Historically; Gustav Fechner psychophysicists and Hermann Ebbinghaus memory studies on himself • Currently used in clinical, cognitive and neuropsychology • Individuals with special needs or aptitudes • Donny the autistic savant • The two major types of single-case research designs are: • case study mostly in clinical • neurologist Oliver Sacks • single-subject experimental designs • N=1 experimental designs • uses manipulation of variables

2. Case Study Method • Case study: An intensive description and analysis of a single individual. • For example: Genie “feral child” • Data: clinical observations, self-report, archival data (e.g., medical records) • Case studies typically report the results of a treatment using qualitative data • Major problem: Lack of control • extraneous variables such as home and work environments that influence the client’s symptoms • Use of simultaneous treatments

3. Box 9.1 PTSD in Chimpanzees • Case study of a 14-year-old adult male chimpanzee who was rescued at the age of nine. • Behavior was observed for a seven-day period and care givers were interviewed to get background information. • Chimpanzees who experience early maternal separation and restrictive captivity exhibit abnormal behaviors such as rocking behavior, self-clasping and self- injurious behavior which are similar to posttraumatic stress disorder. • Because of the similarities to PTSD in humans • chimpanzees who have been abused in this way could benefit from the same type of treatment that is used with humans

4. BOX 9.1 CAN CLIENTS BE THEIR OWN THERAPISTS? • Self-management training (SMT), a therapeutic strategy which capitalizes on the advantages of brief therapies • The client is taught how to assess problems along behavioral dimensions and to develop specific tactics, based on existing treatment techniques • client takes on the dual role of client and therapist, while the therapist takes on the role of supervisor • The case of Susan • Behavioral therapy for anxiety-arousing situations • structured homework assignments which constituted successive approximations of her behavioral goals • had her keep records of her progress.

5. Case Study Method • Advantages of the Case Study Method: • Source of ideas about behavior • Insights into possible causes of people's behavior • A source of research hypotheses • Opportunity for clinical innovation • An opportunity to try a new therapeutic technique such as SMT • if the new technique is successful with an individual it may be generalizable to others with similar needs • Method for studying rare phenomena • Unique individuals such as Geannie or Donnie commercial rarely that they only can be studied as individual cases

6. Case Study Method • Challenge to theoretical assumptions • Unique individuals may demonstrate behavioral or cognitive characteristics that do not fit with current theory which may require adjusting the theory • Tentative support for a psychological theory • Characteristics are unique individuals may support a specific theory. • For example the patient H.M.(see Box 9.3) who had severe amnesia supported the concept of having separate short-term and long-term memory • Complement to the nomothetic study of behavior • The idiographic approach by focusing on the individual provides an understanding of behavior and cognition at the level of detail and complex of the that cannot be studied in groups of individuals.

7. Case Study Method • Disadvantages of the Case Study Method: • difficulty drawing cause-and-effect conclusions (limited internal validity), • possible biases when interpreting outcomes due to observer bias and biases in data collection (e.g., due to poor memory), and • problem of generalizing findings from a single individual (limited external validity)

8. Thinking critically about testimonials based on a case study • Case studies provide great anecdotal evidence and “testimonials.” • Case studies that appear in the popular press are rarely scientific. • People want to believe that the treatment in these testimonials will work for them, but often they do not. • It’s better to pay attention to the results of single-subject experiments.

9. Single-Subject (small-N) Experimental Designs • Single-subject experimental designs have their roots in B. F. Skinner’s approach called applied behavioral analysis. • Single-subject designs improve on case studies, because the researcher attempts to gain more scientific control.

10. B. F. Skinner’s approach called applied behavioral analysis.

11. FIGURE 9.2 Applied behavior analysis is used to investigate methods of controlling maladaptive behavior of children and adults.

12. Characteristics of Single-Subject Experiments • Critical feature of single-subject designs: An independent variable is examined: • treatment • no treatment “control” • Researchers compare treatment conditions for one individual whose behavior is continuously monitored (repeated measures). • Monitor behavior continuously • Search for discontinuity in behavior following implementation of treatment • Clinical treatment for Entomophobia “insectophobia” • A case study of behavioral assessment and treatment of insect phobia

13. BOX 9.4ADVANTAGES OF SINGLE-SUBJECT DESIGNS OVER GROUP DESIGNS: LESS CAN BE MORE • Single-subject experimental designs may be more appropriate than multiple-group designs for certain kinds of applied research • when research is directed toward changing the behavior of a specific individual. • Outcome of a group experiment may lead to recommendations about what treatments are effective “in general” in modifying behavior. • In a multiple-group design, a potentially beneficial treatment must be withheld from individuals in order to provide a control group

14. Single-Subject Experimental Designs The baseline condition is used to describe behavior before treatment is provided, Average of baseline is predictive of what behavior will be like in the future without treatment.

15. Single-Subject Experimental Designs Compared to baseline, the behavior decreases after treatment is implemented. Although this pattern of data suggests the treatment was effective, some other factor that occurred at the same time as the treatment could have caused the frequency of behavior to decrease.

16. The ABAB Design Baseline and Treatment conditions are contrasted in the ABAB Design Illustration of a treatment effect • Frequency of behavior decreases during treatment (B) • Reverses when treatment is withdrawn (2nd A) • Reverses again during treatment (2nd B) • “Reversal design”

17. ABAB Design Illustration of no reversal • Frequency of behavior does not reverse when treatment is withdrawn (2nd A) • Difficult to determine whether treatment was effective

18. ABAB Design • Methodological Issues Associated with ABAB Designs • If behavior does not reverse back to baseline levels after treatment is withdrawn, researchers cannot conclude that treatment caused the initial behavior change. • A variable other than treatment may have caused the behavior to change. • Treatment may have promoted change, and then other variables (e.g., positive attention) may persist to maintain behavior change. • Some behaviors may not be logically expected to change once improved (e.g., when new skills are learned).

19. Effects of facial screening on maladaptive behavior • Eight-year-old girl who engaged in spoon banging behavior during meal time • Face screening is a technique of placing a soft cloth over the face to interrupt the behavior • Produce a clear definition of spoon banging • Assess the amount of spoon banging during 15 minute eating sessions to provide a baseline across 16 sessions • On day 17 facial screening technique was introduced • facial screening continued until session 33 • Return to baseline condition with no facial screening until session 48 • Repeat the facial screening technique until session 64

21. ABAB Design • Ethical considerations • Is it ethical to remove a treatment that appears to be beneficial (i.e., implement the second “A” baseline stage)? • Dilemma between goal of understanding and goal of creating change.