Abnormal Psychology: Research Methods

Basic Components of Research

• Starts with a hypothesis or “educated guess”
  • Not all hypotheses are testable
  • Hypotheses in science are formulated so that they are testable
• Research Design: a method to test hypotheses
  • Independent variable: the variable that causes or influences behavior
  • Dependent variable: the behavior influenced by the independent variable

Considerations in Research Design

• Internal validity vs. external validity
  • Internal validity: extent to which results of a study are due to the independent variable
  • External validity: extent to which results of a study are generalizable to the population it’s studying
• Ways to increase internal validity by minimizing confounds
  • Use of control groups
  • Use of random assignment procedures
  • Use of analogue models

Statistical vs Clinical Significance

• Statistical methods – branch of mathematics
  • Helps to protect against biases in evaluating data
• Statistical vs. clinical significance
  • Statistical significance – asks are results due to chance?
  • Clinical significance – asks are results clinically meaningful?
  • Statistical significance does not imply clinical meaningfulness
• Balancing statistical versus clinical significance
  • Evaluate effect size
  • Evaluate social validity

Studying Individual Cases

• Case study method
  • Extensive observation and detailed description of a single client
  • Foundation of early historic developments in psychopathology
• Limitations
  • Lacks scientific rigor and suitable controls
  • Internal validity is typically weak
  • Often entails numerous confounds

Research by Correlation

• Correlation: assess the degree to which levels of certain variables are linked to levels of other variables
• The nature of correlation
  • Statistical relation between two or more variables
  • No independent variable is manipulated
  • Range from –1.0 to 0 to +1.0
  • Negative vs. positive correlation
• Necessary in situations where you can’t manipulate variables
• Limitations
  • Does not imply causation
  • Problem of directionality

Epidemiological Research

• An example of the correlational method
• Surveys large groups of people to get a picture of an entire population
• Examines incidence, prevalence, and course of disorders
  • Examples – AIDS, trauma following disaster

Research by Experiment

• Nature of experimental research
  • Manipulate independent variable
  • Observe effects on dependent variable
  • Attempt to determine causal relationships
  • Premium on internal validity
• Group Experimental Designs
  • Involves manipulating a variable (i.e., introducing or withdrawing something in a controlled way)
  • Clinical trial: experiment designed to evaluate the effectiveness of a treatment
  • Example: Administering a drug

Control Groups in Clinical Trials

• Control group: provides a comparison point
  • Often matched to demographics of experimental group
  • Placebo: some participants are given an inactive treatment (e.g., sugar pill), but participants don’t know which treatment they are getting
  • Double-blind: participants and assessors are unaware of what kind of treatment participants are getting
• Placebo effect: something changes simply because the participant expects the change to occur (e.g., expecting to feel better when taking an inactive pill)

Single-Case Experimental Designs

• Nature of single subject design
  • Rigorous study of single cases
  • Manipulate timing and nature of experimental conditions
  • Frequent repeated measurement of outcomes is critical
  • Permits conclusions about changes over time relative to the introduction and withdrawal of certain variables
• Types of single-subject design
  • Withdrawal designs
  • First establish a baseline, then introduce treatment
  • Then, stop treatment to see if behavior/symptoms return to the way they were before treatment
  • May present ethical concerns if an efficacious treatment is removed
  • Multiple baseline designs
  • Start treatment at different times in different conditions (e.g., in home vs. school settings) – see if changes occur in conjunction with introduction of treatment
  • Improves internal validity

Studying Genetics

• Behavioral genetics
  • Interactions of genes, experience, and behavior
  • Phenotype vs. genotype
  • Genotype: genetic makeup
  • Phenotype: observable characteristics (e.g., eye color, degree of shyness)
  • Endophenotype: genetic mechanism that contributes to problems causing certain symptoms
  • Example: Group of genes responsible for impairing working memory in schizophrenia
• Family Studies
  • Proband: The person who has the trait of interest (e.g. someone who has schizophrenia)
  • If there is a genetic influence, expect to see the trait more in first-degree relatives compared to second-degree
  • Familial aggregation: tendency of a disorder to run in families
  • Issue of shared environment: families usually live together, so similarities may be due to environmental factors as well as genetics
• Adoption studies
  • One way to separate the effects of the environment
  • Sibling pairs separated after birth: Do they show similarities even if they were raised in different environments?
  • Are adopted children more similar to their birth parents (genetics) or adoptive parents (environment)?
• Twin studies
  • Compare identical/monozygotic twins against fraternal/dizygotic twins
  • If a trait is genetic, expect to see greater concordance in identical twins (similar environment and same genetics) compared to fraternal twins (similar environment, different genetics)
  • Can be combined with adoption studies: If identical twins are both adopted separately and raised apart, shared outcomes are more attributable to genetics
• Genetic linkage studies and association studies
  • Examine known genetic markers (certain gene whose location is known)
  • Compare these genetic markers against the trait being studied
  • If the genetic marker tends to co-occur with the trait, conclude that the trait is probably caused in part by genes that are in close proximity to the genetic marker (e.g. on the same chromosome)
  • Genetic linkage studies occur in groups of people who all have the trait of interest
  • Association studies occur in people with and without the trait of interest

Studying Behavior Over Time

• Prevention research
  • Health promotion: increasing healthy behavior in entire population (even people not at risk for developing disorders)
  • Universal prevention: target specific risk factors but not specific people
  • Selective prevention: targets groups of people at risk
  • Indicated prevention: targets specific individuals who are showing early signs of a disorder
• Time-based research strategies
  • Cross-sectional designs: take a cross section of the population at different age groups
  • Compare cohorts (age groups) on traits of interest
• Longitudinal designs: study one group of people over time
  • Have to take into account specific experiences of the generation being studied (cross- generational effect)

Studying Behavior Across Cultures

• Value of cross-cultural research
  • Overcoming ethnocentric views
  • Increases understanding of
  • Etiologies
  • Symptom presentations
  • Treatments
• Difficulties in cross-cultural research
  • Definitions of abnormal behavior
  • Variance in presentation
  • Availability of valid assessment instruments may be limited

Research Programs

• Components of a research program
  • Set of interrelated research questions
  • Draw on several methodologies in finding answers
  • Conducted in stages, often involving replication
• Allows for more nuanced, complete picture of a phenomenon
• Replication is critical
  • Protects against fluke results

Research Ethics

• Sometimes, needs of science (e.g., designing a good experiment) are at odds with needs of research participants (e.g., need for treatment)
  • Research ethics determine the degree to which each should be prioritized
• Ethic determined by institutional review boards (IRBs) and the APA ethics code
  • Oversee the rights of human subjects participating in research
  • Maje sure research and data are handled responsibly
• Ethical principals
  • Informed consent
  • Became more widely discussed after Nazis had forced people to participate in research in WWII
  • Competence: ability to provide consent
  • Voluntarism: lack of coercion
  • Full information: necessary information to make an informed decision
  • Comprehension: understanding about benefits and risks of participation

\