Foundations and Biological Bases of Psychology: Scientific Origins, Research Principles, and Genetics

Psychology’s Philosophical and Scientific Origins

Historical Influences on Psychology

Psychology did not become a scientific discipline until the late 1800s. Its development was shaped by influences from ancient medicine, physics, evolutionary theory, and medicine.

• Ancient Greek Medicine:

  • Hippocrates: Proposed that personality was determined by four bodily humors (fluids): blood, yellow bile, black bile, and phlegm. Each humor was linked to health and personality traits.

  • Galen: Expanded on Hippocrates, associating humors with temperaments:

    • Sanguine (blood): impulsive, pleasure-seeking, charismatic

    • Choleric (yellow bile): ambitious, energetic, aggressive

    • Melancholic (black bile): independent, perfectionist, introverted

    • Phlegmatic (phlegm): quiet, relaxed, content with life

• Physics: Gustav Fechner (1801–1887) studied sensation and perception, coining the term psychophysics to describe the study of the relationship between physical stimuli and mental phenomena.

• Evolutionary Theory:

  • Charles Darwin: Proposed that genetically inherited traits aid survival and reproductive success.

  • Behavior is shaped by natural selection to help ancestors survive (e.g., memory, emotions, social bonds).

• Medicine:

  • Clinical psychology influenced by medical models of mental disorders.

  • Brain localization: certain brain areas control specific abilities and personality traits.

Influence from Social Science

• Disciplines such as economics, sociology, and anthropology contributed statistical methods for measuring human traits.

• Nature vs. Nurture: Debate over the influence of heredity (genetics) and environment on behavior and mental processes.

• Epigenetics: Genetics can change through environmental influence (e.g., generational trauma).

Major Schools of Thought

• Structuralism:

  • Wilhelm Wundt: Established psychology as an independent field, focused on introspection.

  • Edward Titchener: Analyzed conscious experience by breaking it into basic elements (like molecules in chemistry).

• Functionalism:

  • William James: Studied the purpose and function of behavior and consciousness. Emphasized adaptation to environment.

• Behaviourism:

  • Dominated North American psychology in the early 20th century.

  • Focused on observable behavior, minimizing reference to mental processes.

  • Ivan Pavlov: Classical conditioning (e.g., dogs salivating at a bell).

  • John Watson: Only observable behaviors should be measured. Famous for the "Little Albert" experiment (conditioning fear in a child).

• Social and Cultural Influences:

  • Social psychology: Study of how people’s behavior and mental processes are influenced by others.

  • Personality psychology: Study of how personality characteristics influence behavior and actions.

  • Kurt Lewin: Founder of modern social psychology; behavior is a function of environment.

• Gestalt Psychology: Focuses on perception as a whole, not just the sum of parts.

• Cognitive Psychology: Studies memory, thinking, language, and other cognitive processes.

• Humanistic Psychology: Emphasizes individual potential, self-actualization, and personal growth (e.g., Carl Rogers, Abraham Maslow).

Neuroscience and Biological Bases

• Donald Hebb: Proposed that learning involves changes in neural pathways; "cells that fire together wire together."

• Wilder Penfield: Developed brain mapping techniques using electrical stimulation in awake patients.

Women in Psychology

• Anne Freud and Karen Horney: Advanced understanding of personality and mental health.

• Virginia Satir: Developed family therapy approaches.

Neuroimaging Explosion

• Functional Magnetic Resonance Imaging (fMRI): Allows visualization of brain activity in 3D space.

Positive and Applied Psychology

• Positive Psychology: Focuses on well-being, self-acceptance, and positive social relationships.

• Applied Psychology: Uses psychological methods to solve real-world problems (e.g., in schools, workplaces, military).

• Industrial Psychology: Ensures fair treatment of employees in the workplace.

Principles of Psychological Research

Types of Research

• Basic Research: Seeks to increase fundamental knowledge.

• Applied Research: Uses findings to solve practical problems.

Criteria for Research

1. Objective, Valid, and Reasonable Measurements

   • Measurements must be consistent and reliable across instruments and observers.

   • Operational Definitions: Clearly define variables and procedures for measurement.

   • Reliability: Consistency of measurement (e.g., similar results over time).

   • Validity: Extent to which a measure assesses what it claims to measure.

2. Generalizability

   • Findings should apply to populations beyond the study sample.

   • Random sampling helps ensure diverse representation.

3. Use of Techniques that Reduce Bias

   • Random assignment, double-blind procedures, and careful study design help minimize bias.

   • Social Desirability Responding: Participants may answer in ways that make them look favorable; can be reduced with blind procedures.

4. Made Public

   • Research should be published and open to scrutiny.

Characteristics of Poor Research

1. Lack of falsifiable hypothesis

2. Anecdotal evidence (personal stories instead of systematic data)

3. Biased selection of data

4. Appeal to authority or common sense without evidence

Ethics in Research

• Informed consent, voluntary participation, debriefing, confidentiality, and ethical treatment of participants are essential.

• Canadian Tri-Council Research Ethics Code includes:

  • Respect for human dignity

  • Respect for free/informed consent

  • Respect for vulnerable people

Biological Psychology

Genetics of Behavior

Genetics play a significant role in shaping human behavior. Psychologists investigate how genes and environment interact to produce behaviors and traits.

• Gene Expression:

  • Alleles: Different forms of a gene inherited from each parent.

  • Dominant traits: e.g., dark hair, type A blood.

  • Recessive traits: e.g., light red hair, type O blood, hemophilia.

• Behavioural Genomics: Studies how genetic variations impact personality, behavior, and mental health.

• Epigenetics:

  • Examines how environment alters gene expression (e.g., methylation can turn genes on/off).

  • Environmental factors (e.g., trauma, diet) can affect gene expression and be passed to future generations.

• Intergenerational Trauma:

  • Trauma can cause chemical changes in DNA, affecting offspring (e.g., PTSD symptoms passed down).

• Gene Editing (CRISPR):

  • Allows precise alteration of genetic material; potential for treating diseases but raises ethical concerns.

• Genotype and Phenotype:

  • Genotype: Genetic makeup.

  • Phenotype: Observable characteristics (result of genotype + environment).

• Behavioural Genetics:

  • Twin studies: Compare identical (monozygotic) and fraternal (dizygotic) twins to assess genetic influence.

  • Adoption studies: Compare adopted children to biological and adoptive parents (nature vs. nurture).

Neurobiological Basis of Behaviour

• Nervous System:

  1. Receives input from senses

  2. Processes information by relating it to previous experiences

  3. Produces and monitors bodily reactions or output

• Central Nervous System (CNS): Composed of the brain and spinal cord.

• Corpus Callosum: Bundle of nerve fibers connecting the two hemispheres of the brain.

Example Table: Dominant vs. Recessive Traits

Trait	Dominant	Recessive
Hair Color	Dark hair	Light red hair
Blood Type	Type A	Type O
Clotting	Normal	Hemophilia

Key Equations

• Genotype + Environment = Phenotype

• $\text{Phenotype} = \text{Genotype} + \text{Environment}$

Additional info:

• Some content was expanded for clarity and completeness, such as definitions of key terms and examples of research methods.