# 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

• 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

# 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

• 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