Section 5: Experimental Design Flashcards
Experimental Control
(Functioanl Relations; Analysis; Control)
- When a predictable change in behavior [dependent variable-DV] can be reliably produced by the systematic manipulation of some aspect of the individual’s environment [independent variable-IV]
- The analysis dimension of the 7 dimensions of ABA
4 Important Elements of Behavior
DICE
- Behavior is DETERMINED
- the occurrence of any event is determined by the functional relations it holds to other events
- behavior is a natural phenonmenon and subject to the same natural lawas as other natural phenomena
- Behavior is INDIVIDUAL
- behavior is defined as a person’s interaction with the environment
- Groups of people do not behave
- Experimental strategy of ABA is based on single subject methods of analysis
- Behavior is CONTINUOUS
- behavior changes over time
- behavior requires continuous measurement over time
- Behavior variability is EXTRINSIC to the organism
- variability (change in behavior) is the result of environemnt:
- the IV under investigation
- some uncotrolled aspect of the experiment (e.g. the behavior of another child in the classroom)
- uncontrolled factor outside of experiment (e.g. weather changes)
- variability (change in behavior) is the result of environemnt:
When we see variability in our data, what should we do?
- we should attempt to experimentally manipulate factors suspected of causing the variuability in the data to look for causal factors
- seek treatment variables robust enough to overcome variability
6 Components of Experiments in ABA
MS. BEST
- a measurement system and ongoing analysis of data
- at least one subject
- at least one behavior (DV)
- an experimental design
- at least one setting
- at least one treatment (IV)
Experimental Question
- a brief but specific statment of what the researcher wants to learn from conducting the experiment
- ex. what are the effects of the IV on the DV for what population and in what setting?
- ex. the purpose of the study was to see the effects of the IV on the DV.
At Least One Subject (Single-Subject Designs)
(Single-Case Designs; Within-Subject Designs; Intra-Subject Designs)
(one of the 6 components of ABA experiments)
- ABA uses single-subject designs but thats does not mean there’s only 1 subject in the research
- it’s called single subject because the subject as as their own control
- repeated measures of the subject’s behavior during each phase of the study provide the basis for comparing experimental variables as they are presented or withdrawn in subsequent conditions (ie the presence and absence of the IV)
- the individual is exposed to each condition several times over the course of a study
- it’s called single subject because the subject as as their own control
- studies usually involve more than 1 subject– usually 4 to 8
- Each subject’s data is graphed seperately
- ABA does not use group comparison designs (traditionally used in psychology) because group designs mask individual progress
At Least One Behavior
(Dependent Variable)
(one of the 6 componenets of ABA experiments)
- The behavior is the dependent variable.
- DEPENDENT VARIABLE is the variable in the experiment measured to determine if it changes as a result of manipulations of the independent variable. In ABA, the DV must be a socially signficant behavior.
- some studies measure more than 1 DV. Reasons:
- provide data patterns that can serve as controls for evaluating and replicating the effects of an IV
- Assess if any COLLATERAL EFFECTS occured (a phenomenon in which the IV effects behaviors other than the targeted behavior)
- determine whether changes in the behavior of a person other than the subject occur during the course of an experiment and if such changes can explain changes in the subject’s behavior
- Ex. you are implementing an intervention for your client and the behavior of his brother changes as well
- Ex. you are implementing an intervention for your client and the behavior of his brother changes as well
Collateral Effect
A phenomenon in which the IV effects behaviors other than the targeted behavior
At Least One Setting
(one of the 6 components of ABA experiments)
- Control 2 sets of enviornmental variables to demonstrate experimental control:
- IV (present, withdraw, or vary its value)
- Extraneous Variables (prevent unplanned environmental variation)
- In labs, we can control enviornments better
- When unplanned variations take place, you can wait them out or incorporate them into the design
- repeated measures of behavior tell us whether unplanned environmental changes are of concern
At Least One Treatment
(Independent Variable; Intervention; Experimental Variable)
(one of the 6 components of ABA experiments)
- The IV is the variable that is systematically manipulated by the researcher in an experiment to see whether changes in the independent variable produce reliable changes in the dependent variable.
- …. a particular aspect of the environment that the experimenter manipulates to find out whether it affects the subject’s behavior
A Measurement System and Ongoing Analysis of Data
(one of the 6 components of ABA experiments)
- observation and recording procedures must be conducted in a standardized manner
- standardization involves every aspect of the measurement system (e.g. from the behavior definition to scheduling of observations)
- behaviorists must detect changes in level, trend, and variability
Experimental Design
- the particular arrangement of conditions in a study so that meaningful comparisons of the effects of the presence, absence, or different values of the IV can be made
- Important Rules of Experimental design
- change only one variable at a time
- if you are examining a treatment package (behavioral package), ensure the entire package is presented or whithin drawn at the same time
- select and combine designs that best fit the research question
- change only one variable at a time
Two Types of Experimental Designs
Para = Pyramid of Values
Nonparametric Analysis- the IV is either present or absent during the study (ex. medication is either given or not given in a drug study)
Parametric Analysis - The value of the IV is manipulated. This seeks to discover the differential effects of a range of values. (ex. various doses of medication are given throughout the study)
Treatment Package
- (Behavioral Package)*
- when multiple IVs are bundled together into one program (e.g. a token economy with praise and time out procedures)
Component Analysis
- a process that looks at the effect of each part of a treatment package
- used to determine the effective components of a treatment package
Steady State Responding
(Stable State Responding)
- a pattern of responding that exhibits very little variation in its measured dimensional quantities over a period of time
- Provides the basis for baseline logic
Baseline Logic
- refers to the experimental reasoning inherent in single subject experimental designs
- 3 elements (PAVR)
- Prediction
- Affirmation of the Consequent
- Verification
- Replication
- each of these elements depends on an overall experimental approach called steady state strategy
Steady State Strategy
repeated exposure of a given subject to a given condition while trying to eliminate extraneous influcences on behavior and obtaining a stable pattern of responding before introducing the next condition
Function of Baseline Data
It serves as a control condition but does NOT imply the absence of intervention–it can be the absence of a specific IV.
Benefits of Baseline Data
- to use the subject’s performance in the absence of the IV as an objective basis for detecting change
- to obstain descriptions of ABC correlations for the planning of an effective treatment
- to guide us in setting the initial criteria for reinforcement
- to see if the bheavior targeted for change really warrants intervention
4 Patterns of Baseline Data
DAVS
- Descending Baseline - don’t implement the IV unless its a behavior (functional skill that is being lost) that you need to increase
- Ascending Baseline - don’t implement the IV unless it’s a behavior you need to decrease (challenging behavior)
- Variable Baseline - don’t implement the IV until you’ve controlled all of the environmental variables that may be causing the variability
- Stable Baseline - implement the IV when all of the values of the DV small in a fall range of values
Prediction
(the first part of baseline logic)
- the anticipated outcome of a presently unknown measurement
- data should be collected until stability is clear–the more data the better the predictive power
- main question to ask yourself: are data stable enough to serve as the basis for experiental comparison?
Affirmation of the Consequent
PREDICT THEN AFFIRM YOUR PREDICTION
(the 2nd part of baseline logic)
- Inductive Logic
- If the IV were not applied, the behavior (as indicated by baseline data) would not change
- the experimenter predicts the IV will change the behavior
- if the IV is controlling the DV, the data path in the presence of the IV will show that the DV has changed
- when the IV is present, data show DV has changed
- thus the IV is controlling the DV
Verification
VERIFY THE EFFECTS OF THE IV
(the third part of baseline logic)
- Verification of a previously predicted level of baseline responding by termination or withdrawal of the treatment variable