Читать книгу Abnormal Psychology - William J. Ray - Страница 133

A single-subject design, also referred to as a small-N design, uses the data from one individual participant without averaging it as part of a group of participants. It is assumed that the topic under study is accurately reflected in the single individual and can be controlled appropriately. With this approach, statistical tests are typically replaced with graphical changes. For example, if you wanted to know if a child with autism would respond to a particular type of praise, you could determine this by having a condition in which you give praise and a baseline condition in which you do not. A stronger design, referred to as ABAB, would have a baseline condition (A) followed by the treatment condition (B). This is referred to as a reversal design. Such a design would appear as in Figure 3.9.

single-subject design: also referred to as small-N design, an experiment that uses the data from one individual participant without averaging it as part of a group of participants

Hersen and Bellack (1976) used a multiple-baseline design to demonstrate the effects of a treatment program for a schizophrenic patient. The patient made little contact with others, rarely engaged in conversation, and was compliant even to unreasonable requests. The treatment consisted of training in the development of assertiveness skills and skills for making contact with others. The measures taken over the baseline and treatment sessions were the amount of eye contact while talking, the amount of speaking without prolonged pauses, the number of requests made of another person, and the number of unreasonable requests not complied with. This design requires that baselines be taken for the four measures and that treatments be introduced at different sessions for each of the behaviors to be changed, while measurements of all behaviors are continued. This type of design helps us to determine whether the treatment was specific to a particular behavior (see Figure 3.10). Notice that the treatment was introduced at a different time (dotted vertical line) for each of the four targeted behaviors.

Figure 3.9 ABAB Single-Subject Reversal Design

Source: Dyer, Dunlap, & Winterling (1990).

Figure 3.10 Probe Sessions During Baseline, Treatment, and Follow-Ups for Subject 1

Source: Hersen & Bellack (1976, p. 243).

In a longitudinal study on children with ADHD, a researcher may observe the same group of individuals for a period of years in order to detect changes over time.

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