Overview
This lecture covers research methods and design in AP Psychology, focusing on experimental and non-experimental methodologies, defining variables, sampling, ethical considerations, and the importance of peer review and replication.
Experimental vs. Non-Experimental Methodologies
- Experimental methodology tests hypotheses under controlled conditions to establish causal relationships.
- Non-experimental methods describe behavior but cannot establish causation and include case studies, correlational studies, meta-analysis, and naturalistic observation.
- Correlational studies reveal relationships but do not imply causation due to the third variable problem.
- Case studies provide detailed insights but may be affected by the Hawthorne effect.
- Meta-analysis combines results from multiple studies to reach broader conclusions.
- Naturalistic observation records behavior in real-world settings but may lack context.
Designing a Study
- A hypothesis is a specific, testable prediction about variable relationships and must be falsifiable.
- Operational definitions clearly state how variables are measured or manipulated, enabling replication.
- The independent variable (IV) is manipulated; the dependent variable (DV) is measured.
- Confounding variables are uncontrolled factors that may affect the DV.
Sampling and Group Assignment
- The population is the whole group of interest; a sample is a subset representing this group.
- Random sampling gives everyone an equal chance to participate; stratified sampling ensures representation of subgroups.
- Sampling bias occurs when the sample does not accurately reflect the population, often due to convenience sampling.
- The experimental group receives the IV; the control group receives a placebo.
- Random assignment places participants into groups randomly, increasing validity.
- Quasi-experiments lack random assignment and cannot determine causation.
Procedures and Measurement
- Single-blind procedure: participants do not know their group, reducing participant bias.
- Double-blind procedure: both participants and researchers are unaware of group assignments, reducing experimenter bias.
- Qualitative measures collect descriptive, non-numerical data (e.g., interviews).
- Quantitative measures collect numerical data for statistical analysis (e.g., Likert scales).
Ethics and Participant Protection
- Informed consent means participants understand risks and voluntarily agree to participate.
- Informed assent is used when minors are participants, requiring both the participant’s and guardian’s agreement.
- Ethical studies ensure participant safety, transparency, and include post-study debriefing.
- Institutional Review Boards (IRB) oversee studies involving humans; institutional animal care committees oversee animal research.
- APA ethical standards must be followed in all psychological research.
Conclusions, Peer Review, and Replication
- Peer review evaluates research quality before publication.
- Replication involves repeating studies to verify results and ensure reliability.
Key Terms & Definitions
- Experimental Methodology — systematic testing in controlled conditions to determine cause and effect.
- Non-Experimental Methodology — research methods that describe, but do not explain, behavior.
- Hypothesis — a testable prediction about variables.
- Operational Definition — precise explanation of how variables are measured/manipulated.
- Independent Variable (IV) — variable manipulated by the researcher.
- Dependent Variable (DV) — variable measured for change.
- Confounding Variable — extraneous factor influencing DV.
- Random Sampling — every population member has equal chance of selection.
- Stratified Sampling — sampling from specific subgroups.
- Random Assignment — random placement of participants into groups.
- Single/Double-Blind — procedures to eliminate bias from participants/researchers.
- Informed Consent/Assent — ethical agreements to participate in research.
- IRB — committee that approves ethical research.
Action Items / Next Steps
- Review guided notes, practice resources, and quizzes on variables and research methods.
- Complete quiz questions related to the video’s concepts.
- Check answers and further explanations as provided in the linked resources.