Historical Concepts and Important

Concepts in Single Subject Research

A Historical OverviewAccording to Watson’s argument in early

20th century:

Theoretical goal of behaviorists is prediction and control of behavior.

Psychologists should focus on observable behavior.

Data needs to be collected scientifically and dependent from subjective interpretations which involve consciousness or other mental processes.

A Historical Overview (cont…)Watson Argued that Single subject Research

needs to:

focus on the stimulus-response paradigm for human behavior (i.e., the relationships between stimuli in the environment and the subsequent responses of individuals

A Historical Overview (cont…)In 1930s, Skinner brought a new insight into the

field of Single Subject Design. Skinnerdistinguished between respondent (reflexive)

behavior and operant (or voluntary) behavior.asserted that operant behavior was largely

influenced by events that succeeded, rather than just those that preceded, the behavior.

acknowledged the importance of events that go unseen (cognitive and emotional processes), but also stressed that the responses to those events may still be observable.

The Realm of Applied Behavior Analysis

Baer et al. (1968) noted that research that focuses on socially important behaviors may be applied, behavioral, and analytic.

Applied refers to the interest displayed by society in the problems being studied. Society and the individual have a vested interest in the behavior change and recognize the potential change as a valid endeavor.

Behavioral refers to the pragmatic nature of the study. The focus is on: what a person can do rather than what s/he can say reliable quantification of behavior through systematic observation not only what behavior was changed during a study, but also

whose behavior has changed.

Analytic refers to a believable demonstration that events controlled by the researcher account for the presence or absence of the Behavior in question. Necessary to this characteristic are: Good technical descriptions of procedures (i.e., identification and

descriptions of any techniques applied for the experiment) Replicability of the research in order to lead to generalization of

the results and to show robustness of the procedure.

Basic Concepts and DefinitionsVariables: independent, dependent, &

extraneousPhases: Baseline, intervention, follow-upNotationsX-Y or Line Graph

The X-AxisThe independent variable & phase change linesData pathsThe legend

Basic Concepts: VariablesThe research is to study the existence and nature of a

functional relationship between independent and dependent variables.

Independent Variable (IV): The intervention(s) used to encourage change in human behavior in single subject research (i.e., treatment that the researcher controls in order to influence changes in the dependent variable, through the manipulation of antecedents and consequences).

Dependent Variable (DV): used to measure changes (or the lack of change) in the target behavior. that demonstrate that the desired outcomes of the study

are or are not being achieved. Change in DV is in accordance with or dependent on the

presence, absence or changes in IV.

An example of IV and DVIf positive reinforcement is being applied for

progressively better accuracy in solving mathematics problems, the systematic application of positive reinforcement (independent variable) should have a direct influence on the dependent variable or target behavior (the accuracy in solving math problems).

Extraneous (or confounding) Variables

Any elements of a study that may confuse or obscure the believability that the independent variable and dependent variable share a functional relationship.

Examples include who is delivering the intervention, where the intervention is being delivered, the emotional or physical maturation of the individual subject, the influence of concerned parents or significant others.

Phases of Study: BaselineBaseline Phase:Usually the first stage of the study.Data collected when the Independent variable is not being

implemented. The status quo is maintained unless clearly harmful to le

individual or others. The baseline should end when there is stability in

performance on the dependent variable.Usually baseline should represent at least three

measurements (or observation).But sometimes it could be shortened or skipped altogether

due to ethical demands (e.g., if individual is harmful to himself or others).

The purpose is : To gain a standard of current performance on the

dependent variable by which future changes may be compared.

To capture additional opportunity to glean Information that may reveal important aspects about the dependent variable performance and the environment.

Phases of Study: Intervention

Intervention Phase(s):Usually follows a baseline phase.There may be multiple intervention phases.The independent variable is systematically

implemented during the intervention phase. typically, some level of performance (criterion) on the

dependent variable is identified a priori to determine when the desired outcome has been achieved.

If progress is not achieved, the researcher may alter the dependent variable or even identify a new one altogether.

Phases of Study: Follow-upFollow-up Phase:is implemented after the successful intervention phase.is intended to measure the effects of the independent

variable on the dependent variable over time. strengthens a study by demonstrating the effectiveness

the intervention over time and thereby strengthens the social and ecological validities of the study.

The goal is to remove the independent variable, particularly if it requires a rather intrusive effort to demonstrate that the changes in the dependent variable are relatively permanent and will be maintained even in the absence of the independent variable.

NotationsPhases are denoted by letters.A for Baseline phaseB to Z for intervention phases.An example: researcher implements a baseline

phase (A), followed by an intervention phase (B), followed by a return to a baseline phase (A), followed by the implementation of a new independent variable C. This study would be denoted as an A-B-A-C design.

Also multiple interventions can be implemented in single or multiple phases (e.g., BC-D-E-BE phases).

The X-Y or Line GraphComponents of a line graph include

the dependent variable, the depiction of the passage of time or the

various measures of data, the data path and breaks in that path, the independent variable and its phase change

lines, and the legend.

The Dependent Variable on a line graphExamples of dependent variables are:

how frequently a target behavior occurs, how long it occurs. how intense the behavior is.

The dependent variable is graphed along the y-(or vertical) axis.

Tick marks, or lines that indicate the units of measure (e.g., number of occurrences, number of seconds or minutes, or degrees of intensity), are evenly spaced along that axis.

Most instances the y-axis should be scaled in such a way lat small changes appear small when plotted and big changes appear significant.

The X-Axis on a line graphThe X-axis is used to display the various

measurements made of the dependent variable.The X-axis usually depicts the passage of time. Each tick mark on the x-axis represents an observation

and measurement of the dependent variable (e.g., across 5 min, across 1 hr, a morning, or a whole day)

The length of the observation may in fact vary from tick mark to tick mark, but the results of the observation (the dependent variable) are always expressed in the same terms (e.g., frequency or duration or rate or intensity of a behavior).

The tick marks along the x-axis serve create a visual picture of how the dependent variable has changed as the number of observations increases and, more importantly, in conjunction with changes in the baseline, intervention, and follow-up phases of a study.

The independent variable and phase change lines

Solid vertical lines drawn parallel to the y-axis and perpendicular to the x-axis are used to depict each phase change.

Phases are denoted by letters on the top of the graph.

A dotted or broken line may be drawn similar to the phase change line to depict a change within a phase. For instance when within a phase the observation change from a fixed ratio-5 to the fix ra.tio-10

Data PathsData paths are lines that connect each data point

plotted along the x-y axes. Points are usually connected by a solid line. This solid

line is not typically drawn across phase change lines. The breaks due to unforeseen circumstances (e.g., the

individual becomes sick and in unable to be observed) should be indicated on the graph.

Performance by two or more individuals in the same study or the performance of the same individual under different conditions could be displayed on one graph using different shapes for dotes or color codnig.

The LegendThe legend becomes more important, when

the line graph try to display more complicated data (e.g., multiple data paths or several independent variables).

The legend allows le researcher to abbreviate and to use alphabetic notations instead of whole words, which can be explained in the legend.