psych 3230 chapter 4

Research Methods

• Questions that drive the science of psychopathology include: what problems cause distress or impair functioning, why do people behave in unusual ways, and how to help people adapt in more adaptive ways.

Basic Components of Research

• Research starts with a hypothesis, which is an "Educated Guess."
• Not all hypotheses are testable.
• Scientific hypotheses must be testable and can be rejected or accepted.
• There is a method to test hypotheses called research design.
• The independent variable is a variable that causes or influences behavior
• The dependent variable is the behavior influenced by the independent variable.
• For example: "Exercise reduces depression.”, the IV is exercise, and the DV is the ratings of depression.

Research Design Considerations

• Internal validity determines if the independent variable produces the outcomes.
• External validity determines if the findings can be generalized to other settings, locations, samples, or problems.
• Increase internal validity by minimizing confounds (factors that might make the results uninterpretable).
• Control groups are individual not exposed to IV but the experimental group in every other way, e.g. Group A exercises four days a week, and Group B does not exercise/exercises normally.
• Random assignment procedures include participants assigned to either group or control group to avoid systematic bias.
• Analog models are used to study related phenomena in controlled conditions of a laboratory setting (alcohol).

Internal and External Validity

• There can be a relation between internal and external validity.
• Internal and external validity can be at odds as you want to control confounds that could impact results, but also want results to generalize to the "real world."
• An example of this would be: Exercise that reduces depression. For internal validity, you include only individuals with depression without comorbid disorders.
• This hurts external validity: it is uncommon to see depression without anxiety.
• A compromise is to external validity to improve internal validity.
• Researchers should balance these competing needs.
• One way to do so is through multiple studies.

Statistical and Clinical Significance

• Statistical methods is a branch of mathematics.
• Statistical methods protect against biases when evaluating data.
• Statistical significance determines if the results are due to chance using size of effect, level of significance, and sample size.
• Clinical significance determines if the results are clinically meaningful.
• Statistical significance does not imply that a sample of 200 finds that exercise reduces depression by two points on a rating scale of 1-25.
• Statistical vs clinical significance need to be balanced.
• Evaluate effect size, or statistical measures that tell the magnitude of effect but focuses less on sample size.

Case Study Method

• The nature of the case study includes an extensive observation and a detailed description of a client.
• Case studies are the foundation for early developments in psychopathology.
• Limitations of a case study include: lacks of scientific rigor and suitable outcomes, internal validity is typically weak, and the study often entails numerous confounds.
• Findings of case studies are unique to the individual therefore there is more inference from the researcher.

Correlation

• The statistical relation between two or more variables is called a correlation, which does not manipulate the independent variable.
• Correlation does not mean causation, because it has a problem with directionality (e.g. break-ups and depression, substance use, and impulsivity, or smoking and drinking).
• Correlation ranges from -1.0-+1.0, and can be negative or positive.
• Correlational studies can be used if you cannot randomly assign individuals to groups and can't manipulate the IV (e.g. smoking; psychological disorders).

Epidemiological Research

• Epidemiological research studies incidence, prevalence, and course of disorders, looking for clues about the disorder.
• Incidence is the number of new cases during a specified time.
• Prevalence is the number of people with a disorder at any given time.
• Distribution is more or less common in certain populations.
• Epidemiological research looks at factors associated with frequency of disorders (e.g. gender, SES, certain behaviors).
• The goal is to find clues as to the etiology of disorders.

Experimental Research

• Experimental research is the nature of manipulating independent variables (e.g. therapy or not; meds or not; levels of exercise), and random assignments.
• In experimental research is it attempted to establish causal relations and has a premium on internal validity.
• Group experimental designs focus on control groups, to show that IV is responsible for observed changes and that should be nearly identical to treatment group.
• Placebo and double-blind controls allow to ensure that the treatment effect is not due to expectation.
• It is easy to do with medications, less so with psychological treatment.
• Double-blind studies is when both researchers and participants are unaware of group assignment.

Comparative Treatment Designs

• Comparative treatment designs are the next step after showing that treatment is better than placebo and compare different forms of treatment to similar people (e.g. psychotherapy vs medication vs combo).
• These designs look at treatment outcome, or if a change occurred.
• Dismantling studies break the study into parts while removing or focusing on certain aspects to help figure out the "active" components of treatment.

Single-Case Designs

• Single-subject designs are a systematic study of individuals under a variety of conditions.
• Single-subject designs focus on the rigorous study of single cases and the manipulations of experimental conditions and time.
• Repeated measurement is used, rather than just once before and once after treatment.
• There is a premium on internal validity for single-subject designs.

Single Subject Design Types

• Withdrawal designs (ABAB) takes the baseline, like depression, and gives treatment (Zoloft), then withdraws from their medication, and their depression is reassessed.
• An asset of this can make researchers have a better sense if the treatment caused the changes.
• A liability is the treatments that might be helpful; risk of relapse and is impossible to "withdraw" most psychological treatments (once learned, can't force patient to unlearn them).
• Multiple baseline designs do not start and stop treatment, and starts intervention at different times across settings (home vs school) or behaviors (hitting, talking back, doing homework).
• Multiple baseline designs do not have to withdraw treatment.
• A liability of this design includes still making conclusions based on a small number of people.

Genetic Research Strategies

• Behavioral genetics includes the interaction among genes, experience, and behavior.
• The phenotype (observable characteristics or behavior) vs. genotype (genetic makeup).
• Down syndrome is the phenotype (intellectual disability); and genotype (extra 21st chromosome).

Genetic Research

• Family studies - Examine the behavior pattern/emotional traits in family members (e.g. schizophrenia; alcohol use) but cannot distinguish between environmental and genetic factors.
• Adoptee studies allow the separation of environmental from genetic contributions, like if children are more like adoptive parents or biological parents.
• Results suggest some heritable component that is more so for properly crime than violent crime.
• Twin studies evaluate psychopathology in fraternal vs identical twins with a risk of developing schizophrenia including: Monozygotic twins: 48% and Dizygotic twins: 17%.
• These results require that the "equal environment" assumption is correct.
• Genetic linkage and association studies - locate the site of related genes.

Studying Behavior Over Time

• Rationale and Overview focuses on how the problem or behavior change over time and is important in prevention and treatment.
• Cross-sectional designs take a cross section of the population across different age groups and compare on a certain characteristic (Example: Substance Use).
• Difference are participants in each group cohort, or a member of the cohort being the same age, same historical time and exposed to similar experiences.
• A problem is differences across ages may be due to both age and dissimilar experiences (substance use and 1960s).
• Another problem is the Cohort effect which confounds the effect of age and existence since it tells us little about how problems develop but can tell us that two variables are related but not causal information.
• Longitudinal designs follow one group over time and assess changes in individuals with No cohort effect problem.
• With Longitudinal designs you can get closer to understanding causality (order of relationships; depression leads to fewer friends vs fewer friends leads to depression).
• This design has problems like taking a long time to do, is expensive, must worry about participant attrition, and the study topic may no longer be relevant by the time study completes.
• The cross-generational effect may not be possible to generalize study effects to other groups whose experiences are quite different.

Studying Behavior Across Cultures

• Cross-Cultural research values studying abnormal behavior various cultures, which can be informative and helps to overcome ethnocentric research.
• Issues in cross cultural research clarify how psychopathology manifests in different ethnic groups since the same terminology may look or feel very different across cultures.
• Northwestern cultures tend to emphasize somatic aspects of depression and include different thresholds for abnormal behavior.
• Treatments exists within a cultural context.

Programmatic Research

• The components of a research program include that no one study will definitely answer the question.
• Studies proceed by asking slightly different questions, using slightly different procedures, and conducted in stages, often involving replication.
• Scientific knowledge typically builds incrementally and is REPLICATION.