Chapter 2 Biology of Behavior & Research Methods

Experimental Methods in Psychology

• Placebo effect
  • Definition: A physiological or psychological improvement due to participants' expectations rather than the active treatment.
  • Significance: Highlights how expectation can influence outcomes and confound results if not controlled.
  • Related concepts: Demand characteristics and participant bias can interact with placebo to distort measurements.
• Double-blind procedures
  • Definition: A research design in which neither participants nor researchers know which participants are in the treatment or control group.
  • Purpose: Reduces bias and expectation effects, improving internal validity.
  • Practical note: Often used in pharmacology and behavioral experiments to minimize placebo and observer effects.
• Variables in experiments
  • Independent variable (IV): the variable deliberately changed by the experimenter to observe its effect on the DV.
  • Dependent variable (DV): the outcome that is measured.
  • Confounding variable: any uncontrolled variable that could influence the DV and provide an alternative explanation for observed effects; must be controlled or randomized to isolate the effect of the IV.
  • Notation concepts:
  • The basic relationship can be thought of as: DV = f(IV) + \, \epsilon where \epsilon represents error from unmodeled factors.
  • A more explicit linear form: DV = \beta0 + \beta1 \cdot IV + \epsilon
• Chapter 2: Biology of Behavior
  • Core idea: Neural and hormonal systems underpin behavior and mental processes; biology and psychology are deeply interconnected.
  • Mind-brain relationship: The understanding of how brain activity relates to thoughts, feelings, and actions has evolved, showing that many psychological phenomena have biological bases.
  • Emphasis: Psychology is rooted in biology; studying neural circuits, neurotransmitters, and endocrine signals helps explain behavior.
• Historical perspectives on the mind and brain
  • Plato: Mind is located in the spherical head; early idea of brain-centered mental processes.
  • Aristotle: Mind is found in the heart; alternative historical view prioritizing the heart.
  • Gall and phrenology: Phrenology suggested that mental faculties are localized to specific brain regions; used skull measurements to infer personality traits and abilities.
  • Critical note: Phrenology is now discredited as a pseudoscience, but it contributed to the notion that brain structure relates to function and spurred later localized brain research.
• Brain plasticity and lifelong change
  • Plasticity: The brain changes throughout life, reorganizing after injury or building new pathways based on experience.
  • Mechanisms:
  • Reorganization after damage (functional compensation or re-mapping of tasks).
  • Formation of new neural pathways in response to learning and experience.
  • Implications: The human brain is capable of adapting, which underpins learning, rehabilitation after injury, and skill acquisition.
  • Philosophical implication: The brain is dynamic rather than fixed, supporting growth, recovery, and lifelong learning.
• Connections to prior lectures, foundational principles, and real-world relevance
  • Foundations: Emphasis on empirical methods, controlled experiments, and the need to distinguish correlation from causation.
  • Real-world relevance: Experimental designs (placebo, double-blind) inform clinical trials, medical research, education strategies, and therapy development.
  • Integration with biology: Understanding behavior requires linking neural circuits, hormones, and environmental factors.
• Ethical, philosophical, and practical implications
  • Placebo and deception in research: Use of placebos and blinding raise ethical questions about deception vs. informed consent; ethical guidelines require risk minimization and debriefing.
  • Phrenology as a cautionary tale: Highlights the importance of evidence-based science and avoiding simplistic mappings of traits to brain regions.
  • Plasticity in rehabilitation: Supports optimistic yet realistic expectations for recovery after injury; informs rehabilitation protocols and educational approaches.
  • Practical considerations: Controls for confounding variables, appropriate randomization, and robust experimental design are essential for valid inference.
• Key terms and formulas (glossary with notation)
  • Placebo effect: the improvement in a patient due to expectations rather than the active treatment.
  • Independent variable: IV — the manipulated factor.
  • Dependent variable: DV — the measured outcome.
  • Confounding variable: a variable that can influence the DV outside of the IV; must be controlled.
  • General model: DV = \beta0 + \beta1 \cdot IV + \epsilon where \epsilon captures unmodeled influences.
  • Brain plasticity: the brain's ability to reorganize itself by forming new neural connections throughout life.
  • Historical notes: mind-brain localization debates (head vs heart) and the rise and fall of phrenology as a methodological caution.