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Chapter 2Research Methods
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Basic Terms and Definitions
• Variable – environmental characteristic that can change
• Independent variable – aspect of experiment that can be systematically varied by experimenter
• Dependent variable – aspect of experiment that can vary freely
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Table of Scientific Terms
Independent Variable
What the experimenter manipulates
X variable
The “Cause”
Bernard’s diet
Environmental Change
Dependent Variable
What is measured
Y variable
The “Effect”
Chemistry of urine
Behavior
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Functional Relationships
• Relationship between changes in an independent variable and changes in a dependent variable.
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Conditions for Causation
• covariation of x and y• Change in independent variable precedes a change
in dependent variable• replication
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Internal and External Validity in Experiments
• Internal validity - change in dependent measure attributed to changes in independent variable– History– Maturation– Reactive measurement– Instrument decay
• External validity - generalization
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Establishing Operations
• What makes reinforcers reinforcing?• Context of behavior - environment-behavior
relationships are conditional– a) increase in the momentary effectiveness of event
supporting operant behavior
– b) increased momentarily responses had in past produced event.
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Contiguity and Contingency
• Contiguity (temporal) – extent to which events occur closely together in time.
• Contiguity (spatial) – extent to which events are situated close together in space.
• Contingency – dependent relationship between two events.
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Measurement of Behavior
• Behavioral Definitions– Objective
– Unambiguous
• Can maintain a record
– Rate of response – frequency per unit of time
– Cumulative record
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Measurement of Behavior
• Response Measures– Rate of response –frequency per unit time (probability)
– Intensity – force or magnitude
– Duration – length of time individual repeatedly or continuously performs a certain behavior.
– Speed – amount of time required to perform a complete episode of a behavior from start to finish
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Measurement of Behavior
• Response Measures– Latency – length of time required for the behavior to
begin.
– Interval Recording – measurement of whether or not a behavior occurs within series of continuous intervals
– Time Sample Recording – measurement of behavior within a series of discontinuous intervals
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Measurement of Behavior
• Response Measures– Topography – exact physical form of behavior
– Errors
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Research Design
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Research Designs
• Descriptive Research – describing behavior and situation it occurs.– Naturalistic Observation – systematic observation and
recording of behavior in its natural environment.
– Case studies – intensive examination of one or a few individuals.
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General Principles of Research
• Research design
– There are many methods used to study psychological concepts and phenomena.
– We start by asking ourselves “what happens, and under what circumstances does it seem to occur?”
– We try to choose the best procedure. Each method has advantages and disadvantages.
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General Principles of Research
• Observational (non-experimental) Research Design
– Naturalistic Observation:
• Careful monitoring and examination of what people and animals do under more or less natural circumstances.
– Example: Dr. Jane Goodall’s decades-long observation of chimpanzees in the forest of Gombe, recording their social organization and biological functioning.
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General Principles of Research
• Observational Research Design
– Case History:
• A thorough observation and description of a single individual, appropriate only when done for an unusual condition or circumstance.
– Example: The case of Phineas Gage, whose bizarre and unfortunate accident taught medical doctors and psychologists much about the nature of the prefrontal cortex of the brain.
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General Principles of Research
• Observational Research Design
– Survey:
• A survey is a study of the prevalence of certain beliefs, attitudes, or behaviors, based on people’s responses to specific questions.
– Example: Albert Kinsey’s 1948 survey of the sexual preferences and habits of Americans was ground breaking, although not by any means beyond criticism.
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General Principles of Research
• Observational Research Design
• Surveys
– A Few Concerns About Survey Research:
• Problems with obtaining a random or representative sample
– Competence or honesty of those who respond
– The wording of the questions
– Surveyor bias
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General Principles of Research
• Correlational Studies
– Correlation
• Correlation is a measure of the relationship between two variables which are both outside of the investigator’s control.
• Examples of variables include aspects such as: height, weight, socio-economic level, number of years of education.
• The mathematical estimate of the strength and direction of a correlation is the correlation coefficient.
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Research Designs
• Experimental Research– Control Group Designs
• Random assignment of subjects to either experimental group or control group
• Large number of subjects
• Average data may not be representative of individual subject
• Results significant at end of experiment
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Single-Subject Design
• Require a few subjects to conduct entire experiment.– Simple-Comparison (AB)
Design – baseline compared to treatment.
• Does not control for the possibility that another event occurred during the treatment phase.
• Does not clearly demonstrate a functional relationship.
• Used when A phase cannot be recovered
AB DESIGN
Days
1 2 3 4 5 6 7 8 9 10 11 12N
um
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of
Urg
es
0
5
10
15
20
Baseline (Phase A)
Treatment (Phase B)
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Single-Subject Design
• Reversal (ABAB) Design– Repeated alternations
between baseline and treatment.
• Entire experiment within single subject
• Statistical tests not needed (behavioral relevance not statistical significance.
• Ethics of reversal
ABAB DESIGN
Days
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Nu
mb
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f U
rge
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0
5
10
15
20 Baseline (Phase A)
Treatment (Phase B)Treatment (Phase B)
Baseline (Phase A)
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Single-Subject Design
• Multiple-Baseline Design– Treatment instituted at
successive points in time for two or more persons, settings, or behaviors
– No need to withdrawal treatment
– Requires more than one situation
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Single-Subject Design
• Changing-Criterion Design– Procedure to produce
gradual change
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Logic and Experimental Design
• Even the most well develop experiment cannot prove a cause and effect relationship
• Research design is based on a logical fallacy– Affirmation of the consequent
– We hypothesize if A then B
– We look for B, finding it we surmise that A occurred
– But did it????
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Single Subject Research
• Replication– direct replication
– systematic replication
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Animals in Behavioral Research
• Control history– Phylogenic and ontogenetic
• Control of context• Ethics of research with humans• Generalization• Ethics of research with non-humans
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General Principles of Research
• Experiments
– Possible problems in carrying out and interpreting the results of experiments:
• Ethical Considerations : In doing research with humans or animals, researchers must way possible harm that may be inflicted against the usefulness and other benefits that may be gained.
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General Principles of Research
• Ethical Concerns in Research involving Human Subjects
• Safeguarding human subjects’ well-being:– Use of informed consent: Subjects are advised on what
to expect and explicitly state that they agree to continue.
• Institutional Research Board (IRB) Approval: A university or other reputable institution appoints a panel of qualified judges who review all research proposals before the actual experiment begins.
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General Principles of Research
• Ethical Concerns in Research involving Human Subjects
– American Psychological Association standards: The criteria for appropriate treatment of humans who are experimental subjects are well known to members of this largest professional organization in the science. Censure and expulsion are possible consequences for those who do not follow these procedures.
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General Principles of Research
• Ethical Concerns in Research involving Animals– Though highly controversial, research studies that use
animals to help us understand the body and brain have been essential to progress in medicine and psychology.
• Criteria for care and use of animals are established by professional organizations:
– APA
– The Neuroscience Society
– Animal care committees at research institutions
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General Principles of Research• Ethical Concerns in Research involving Animals
– Following the guidelines, animal care committees strive to:
• Ensure that research animals are treated humanely
• Ensure that any pain and discomfort are kept to a minimum
• Ensure that all alternatives are examined before animals are subjected to potentially painful procedures
– Nonetheless, this area continues to be one of great debate, and no compromise between the sides ever seems 100% satisfactory.