Research Methods

Research Methods Overview

  • Definition of Variable: Characteristics or quantities that can be measured or manipulated.

    • Independent Variable (IV): Manipulated to test its effect on the dependent variable.

    • Dependent Variable (DV): Outcome measured as a result of the IV.

    • Extraneous Variables: Uncontrolled variables affecting outcome; can lead to confounding variables.

Types of Variables

  • Independent Variables (IV): Example is music in a learning test.

  • Dependent Variables (DV): Example is learning performance measured.

  • Extraneous Variables:

    • Participant Variables: Individual differences (e.g., mood, intelligence).

    • Situational Variables: Environmental impacts (e.g., temperature, noise).

Controlling Extraneous Variables

  • Standardization: Keeping procedures consistent for all participants.

  • Counterbalancing: Varying the order of conditions for different participants.

  • Randomization: Assigning participants to groups randomly to eliminate bias.

  • Single-Blind Technique: Participants unaware of the study's aim.

  • Double-Blind Technique: Both participants and researchers unaware of condition assignment.

Research Process

  • Hypothesis Formation: Testable statement about the relationship between variables.

    • Directional Hypotheses: Predict a specific relationship.

    • Non-Directional Hypotheses: Predict a relationship without specifying direction.

    • Null Hypothesis: States no relationship exists (e.g., music has no impact on sleep).

    • Alternative Hypothesis: One variable affects the other without direction.

Operationalization and Pilot Studies

  • Operationalization: Defining abstract concepts into measurable variables.

  • Pilot Studies: Pre-study to assess feasibility and control for confounding variables.

Sampling Techniques

  • Opportunity Sampling: Participants chosen for availability; fast but may be biased.

  • Volunteer Sampling: Participants self-select; committed but may be unrepresentative.

  • Random Sampling: All have an equal chance of selection; likely representative but may be biased towards demographic.

Experimental Methods

  • Types of Experiments:

    • Laboratory Experiment: Controlled environment, manipulation of IV.

    • Field Experiment: Natural settings, manipulation of IV.

    • Natural Experiment: Change occurs naturally; researcher does not manipulate IV.

Evaluation of Experiments

  • Laboratory Experiments:

    • Strengths: Control over extraneous variables; establishes causal relationships.

    • Weaknesses: Artificial settings may affect behavior; low ecological validity.

  • Field Experiments:

    • Strengths: Natural behavior; high ecological validity.

    • Weaknesses: Uncontrolled extraneous variables; ethical issues of consent.

  • Natural Experiments:

    • Strengths: Observes real-world issues; high ecological validity.

    • Weaknesses: Hard to control variables; causality difficult to establish.

Experimental Design Types

  • Independent Measures: Different participants for each condition.

  • Repeated Measures: Same participants for all conditions.

  • Matched Pairs Design: Paired participants based on a characteristic.