SHDS2291 Introduction to Psychology: Research Methods

Introduction to Psychology: Lecture 2 - Research Methods

A. The Scientific Investigation

  • Psychology as a Science: Psychology relies on the scientific method to minimize bias and errors in measurement.
  • Key Concepts:
    • Theory: Provides explanations, organizes, and predicts observable behaviors or events.
    • Hypothesis: A tentative and testable explanation derived from observations and existing theories. It can be viewed as an educated guess about the relationships between variables.

B. The Scientific Method

  1. Steps in a Scientific Investigation:
    1. Formulate a Hypothesis: Establishes a basis for the investigation.
    2. Design a Study: Create an experimental framework to test the hypothesis.
    3. Collect the Data: Gather information through empirical research.
    4. Analyze the Data: Interpretation of the collected information.
    5. Report the Findings: Share results with the scientific community.
    6. Evaluate Theory: Support, revise, or reject the theoretical framework based on findings.

B. Research Methods

  1. Descriptive Methods: Facilitate formation of testable hypotheses.
    • Observation: Unintrusive documentation of behaviors in natural settings.
    • Case Study: In-depth analysis of one or a few individuals using various data sources: interviews, observations, historical records.
    • Survey: Collect standard data by asking a population sample standardized questions.
      • Population vs. Sample:
      • Population: The entire group of interest.
      • Sample: A subset of individuals that should represent the population effectively (utilizing random sampling for representativeness).
  2. Correlational Research: Understanding relationships between two variables.
    • Variables: Anything that can change or be measured (e.g., IQ, height).
    • Correlation Coefficient (r): Indicates the degree and direction of the relationship ranging from -1.00 to +1.00.
    • Scatter Plots: Visual representation of correlations (positive, negative, or none).
  3. Experiments: The only method that can establish cause-and-effect relationships by manipulating the independent variable (IV) and observing the dependent variable (DV).
    • Independent Variable (IV): The factor manipulated by the researcher.
    • Dependent Variable (DV): The measured outcome in response to the IV.
    • Operational Definition: Specific definition of a variable allowing it to be measured once the experimental conditions are set (e.g., defining aggression as the frequency of aggressive play).
    • Experimental Groups vs. Control Groups: Experimental groups undergo the IV manipulation, while control groups do not, ensuring comparison.
    • Random Assignment: Randomly allocating subjects to groups helps eliminate bias from extraneous variables.

C. Research Evaluation

  1. Flaws in Research & Solutions:

    • Sampling Bias: Use random sampling to achieve accurate representation.
    • Confounding Variables: Employ random assignment to control extraneous variables.
    • Placebo Effects: Utilize placebo treatments and single-blind procedures to mitigate biases.
    • Social Desirability Bias: Implement lie scales to assess social desirability in participant responses.
    • Observer/Experimenter Bias: Use double-blind procedures to prevent bias.

  2. Ethical Issues:

    • Ensure no harm comes to participants.
    • Uphold informed consent, confidentiality, and address deception with debriefing.

D. Conclusion

  • Assigned Readings: Pastorino & Doyle-Portillo (Ch. 1 pp.7-22)