Principles of Scientific Research

Principles of the Scientific Method

  • Random Selection

  • Evaluating Measures: Reliability and Validity

    • A reliable test must be valid, but a reliable test can still be invalid.

Openness and Transparency in Science

  • Research should be replicable and reproducible.

  • Incremental and collaborative process.

  • Open Science Movement:

    • Publicly share research,

    • Encourage replication before new research,

    • Preregister studies,

    • Focus on publishing sound science,

    • Emphasize meta-analyses over single studies.

Types of Research

  • Naturalistic Observation: High external validity but low internal validity.

  • Case Study: In-depth study; breadth traded for depth; useful for rare cases.

  • Self-Report and Surveys: Quick data collection; prone to biases and inaccuracies.

Correlational Designs

  • Measure extent of association between two variables.

  • Correlation ranges from -1 to +1:

    • Positive (both variables increase),

    • Negative (one increases while the other decreases),

    • Zero (no relationship).

Experimental Methods

  • Focus on cause-and-effect relationships.

  • Key components:

    • Random assignment,

    • Independent variable manipulation.

Experimental Designs

  • Within-Subjects Design: Manipulation within the same individuals.

  • Between-Subjects Design: Manipulation occurs between groups.

  • Key definitions:

    • Independent variable: manipulated variable,

    • Dependent variable: measured variable.

Confounds and Pitfalls

  • Confounding variables: Differences other than the independent variable.

  • Placebo Effect: Improvement due to expectation;

  • Nocebo Effect: Harm due to expectation.

  • Experimenter Expectancy Effect: Researcher bias impacts outcome.

  • Demand Characteristics: Participant cues affecting outcome.

Statistics in Research

Descriptive Statistics

  • Characteristics of data nature.

  • Measures of Central Tendency:

    • Mean,

    • Median,

    • Mode.

  • Measures of Dispersion:

    • Range,

    • Standard Deviation.

Inferential Statistics

  • Determines generalizability of findings.

  • Statistical Significance (p < 0.05): Probability findings occurred by chance.

  • Practical Significance: Real-world importance of findings.

Ethics in Psychology

  • Ethical considerations in human and animal studies:

    • Informed consent,

    • Protection from harm,

    • Deception and debriefing.

  • Controversies surrounding animal research.