Overview
This lecture covers the scientific foundations of psychological research, detailing the scientific method, variables, operational definitions, types of research methods, data analysis, and research ethics in psychology.
Psychology as a Science
- Psychology is defined as a science studying mental processes and human behavior.
- Science operates on two key beliefs: natural laws exist, and these laws are discoverable and testable.
- Psychologists use the scientific method: observe, hypothesize, test, conclude, and evaluate.
Steps of the Scientific Method
- Observation is prompted by curiosity and leads to identifying variables and forming a theory.
- Hypotheses must be testable and measurable to allow replication and further investigation.
- Testing involves collecting and recording data on the variables.
- Conclusions analyze if results support the hypothesis, affect the theory, and can be generalized.
- Evaluation includes revising theories, peer review, and meta-analysis for validation.
Variables, Operational Definitions, and Sampling
- Independent variable: manipulated or categorized factor (e.g., type of flower).
- Dependent variable: measured outcome affected by the independent variable (e.g., time spent by bees).
- Operational definitions specify exactly how variables are measured for replication (e.g., "1 hour of sunlamp exposure").
- Populations are broad groups; samples are subsets studied to represent the population.
- Random selection and avoiding sampling bias ensure fair representation.
Research Methods in Psychology
- Descriptive research observes and describes behavior without determining cause (includes naturalistic observation, surveys, case studies, correlational studies).
- Experimental research manipulates variables to determine cause and effect, using control and experimental groups with random assignment.
- Double-blind procedures help control for bias in experiments.
Descriptive Research Methods
- Naturalistic observation: systematic, non-intrusive observation (advantage: ethical for sensitive topics; disadvantage: time-consuming, no causality).
- Surveys: direct questioning (advantage: quick, cheap; disadvantage: potential dishonesty).
- Case studies: in-depth study of rare or unique cases (advantage: detailed info; disadvantage: lack of generalizability, no causality).
- Correlational studies: relationship between variables shown with correlation coefficient (advantage: predicts relationships; disadvantage: cannot determine causation).
Experimental Research
- Allows for precise control and identification of causal relationships.
- Requires random assignment to experimental or control groups.
- Uses double-blind procedures to minimize bias.
Data Analysis and Statistics
- Descriptive statistics: summarize data using mean (average), median (middle value), and mode (most frequent value).
- Standard deviation describes variability in data.
- Inferential statistics help determine if results are significant.
Research Ethics
- All human research must be approved by an IRB and follow ethical guidelines: informed consent, protection from harm, confidentiality, and debriefing.
- Animal research is overseen by the Institutional Animal Care and Use Committee, requiring minimization of harm and justification for animal use.
Key Terms & Definitions
- Independent Variable — the factor manipulated or categorized by the researcher.
- Dependent Variable — the outcome measured in the experiment.
- Operational Definition — explicit definition of how a variable is measured.
- Population — the entire group of interest in a study.
- Sample — a subset of the population selected for study.
- Descriptive Research — research that observes and describes behavior without inferring cause.
- Experimental Research — research that manipulates variables to determine cause and effect.
- Correlation Coefficient — statistic expressing the strength and nature of the relationship between two variables.
- Standard Deviation — a measure of how data points vary around the mean.
- Informed Consent — participants’ agreement to partake in research after being informed of potential risks.
Action Items / Next Steps
- Practice identifying independent and dependent variables in example experiments.
- Consider how to operationally define psychological variables (e.g., self-esteem, shyness).
- Review types of research methods and select appropriate methods for hypothetical scenarios.
- Read upcoming textbook chapter on research methods in psychology.