Lecture 01 — Psychology Before Cognitivism

Epistemology and Early Roots of Psychology

• The first evidence of scientific thought appears as early as 5000 BC; psychology as an independent, recognized discipline is relatively young, with its generally recognized birth date in 1879.
• In comparison to natural sciences (biology, chemistry, physics), psychology arrived later on the scientific scene: biology has roots in ancient medicine and flourished with cell theory in the 19th century; physics grew from Babylonian astronomy and Newton’s theory at the end of the 17th century; chemistry modernized with Lavoisier in the late 1700s.
• Psychology’s forebears were philosophy and physiology.
  • Physiology: branch of biology concerned with the functions of living systems; the nervous system is of special interest to psychologists; brain–behavior links were appreciated long before modern neuroscience.
  • The first written brain reference appears in the Edwin Smith surgical papyrus; Greeks and Romans credited with identifying the brain as the top level of the behavioral control system.
  • Modern physiology begins with cell theory, attributed to Schleiden and Schwann in 1839.
• Epistemology and early theories of knowledge
  • Epistemology: branch of philosophy concerned with the nature and origins of knowledge; one view is nativism.
  • Nativism: knowledge exists inborn; Plato suggested learning is uncovering knowledge already possessed but obscured at birth; language and learning are often cited as nativist positions.
  • Rationalism: knowledge results from reasoning; associated with Descartes; knowledge has an intellectual, not sensory, basis; example logic: if BILL > JANE and JANE > JOHN, then BILL > JOHN.
  • Empiricism: knowledge via sensory experience; foundational to scientific psychology; British Empiricists sought to explain complex thought via elementary experiences and associations.
  • Laws of association (British Empiricists): contiguity (togetherness in time), similarity, and frequency; contiguity is often viewed as the primary principle.

Psychophysics: Relating Physical Stimuli to Perceived Experience

• Psychophysics sought to quantify relationships between external physical properties and internal perceptual qualities.
• Ernst Weber: pioneer who proposed a mathematical account of the relation between physical stimuli and perceptual experience; introduced the concept of the just-noticeable-difference (JND).
  • JND: the minimum amount of change in a stimulus required for a person to notice a difference.
  • Example: Present a light on a screen, gradually increase its intensity, and ask the observer to indicate when the light seems brighter; record the required change in intensity.
• Weber’s Law: a mathematical relation linking physical change to perceptual change. Formally:
  • $\Delta R/R = k$
  • where:
  • R = initial stimulus intensity
  • \Delta R = the change in stimulus intensity required for a JND
  • k = constant depending on the physical property and perceptual quality (e.g., wavelength for hue, intensity for brightness)
• Gustav Fechner built on Weber’s work; found Weber’s law is good for moderate ranges but fails at very low or very high stimulus intensities.
• Fechner’s revision: Weber–Fechner law, indicating a non-linear, logarithmic relationship between physical intensity and perceived quality:
  • $S = k \ln I$
  • where S is the perceived quality, I is stimulus intensity, and k is a constant.

Cartesian Dualism and the Mind–Body Problem

• Descartes popularized the mind–body distinction, with physical bodies (including the brain) and a non-physical mind. This is Cartesian dualism.
• The mind–body problem arises from trying to explain how mental and physical events causally relate.
  • If you stay in the domain of physical processes, causal explanations are straightforward.
  • If you stay in the domain of mental events, explanations are possible but linking mental to physical events is difficult.
  • The problem persists as a central philosophical challenge for psychology and neuroscience.

Birth of Psychological Science: Wundt, Structuralism, and Functionalism

• Leipzig, 1879: formal discipline of psychology born when Wilhelm Wundt founded the first laboratory using experimental methods to study psychological questions.
• Wundt’s vision: psychology as the science of mental experience; study consciousness with rigorous methods borrowed from chemistry.
• Two-step plan for a “chemistry of the mind”
  1) Create a periodic table of the elements of consciousness: identify irreducible sensory qualities (e.g., loudness, bitterness, sharpness, redness).
  2) Discover the laws by which these mental elements combine into more complex contents (molecules of consciousness).
• Introspection as a method in Wundt’s lab: trained observers provide reports of raw sensory experiences with minimal interpretation; untrained observers might give conceptual responses (e.g., bananas instead of raw sensory data).
• Today’s view labels introspection as subjective, but Wundt aimed for scientific rigor within his framework.
• Edward Titchener (Wundt’s student) brought these ideas to the U.S.; founded structuralism at Cornell.
  • Structuralism aimed to identify the basic structures of consciousness via introspection.
  • Titchener claimed over 44,000 basic elements of consciousness, categorized into three types: feelings, sensations, and images.
• Functionalism (Harvard): led by William James, who is often called the American father of psychology and the most quoted psychologist.
  • James argued that consciousness is a continuous, flowing stream (the stream of consciousness), not easily dissected into elementary parts.
  • Darwinian influence: the mind as an organ aiding adaptation to environmental challenges.
  • Functionalists (e.g., John Dewey, James Rowland Angell at the University of Chicago) emphasized the functions of the mind in helping organisms adapt and solve problems; they formed a school called functionalism.
  • James did not align himself with a school; he is often viewed as the father of functionalism.
• Mentalism (shared ground of structuralism and functionalism): both schools treated psychology as the study of conscious experience (the mind).
• Growing dissatisfaction with both structuralism and functionalism as a truly scientific psychology.

Emergence of Behaviorism: A New Scientific Focus

• By the early 20th century, many American psychologists were unhappy with the study of conscious experience.
• Watson’s Philosophy (1913): Psychology as the Behaviorist View it. Opening paragraph (paraphrased):
  • Psychology should be a purely objective, experimental branch of natural science.
  • Introspection should not be essential; data should not depend on interpretations of consciousness.
  • There should be no dividing line between human and animal behavior; the behavior of humans is part of the broader behaviorist framework.
• Watson’s behaviorism motto: a science of behavior, not of the mind.
• Four key ideas of Watson’s program (as extracted from the opening of his manifesto):
  1) Behaviorism is a purely objective scientific endeavor.
  2) Mental consciousness cannot be studied scientifically.
  3) Behavior can be studied scientifically and is the proper subject matter of psychology.
  4) A single set of behavioral principles applies to all animals, including humans and nonhumans.

Behaviorist Metaphors and the Learning Theory Framework

• The reflex arc as the guiding metaphor: behaviorism is rooted in the idea that complex behaviors are built from acquired reflexes.
• Pavlov’s work on classical conditioning inspired behaviorists’ emphasis on learned associations between stimuli and responses (S-R theory).
• Two major epistemic commitments of behaviorism:
  • Empiricism: knowledge arises from experience; learning is driven by environmental interactions.
  • S-R learning: associations form between environmental stimuli (S) and responses (R) with no reference to hidden mental states.
• Similarities to British Empiricism: emphasis on learning via experience and simple associations; difference: behaviorists focus on stimulus–response links in the environment rather than mental contents.
• Organism’s role in learning: behaviorism views the organism as largely passive; the environment elicits responses, not vice versa (e.g., a pigeon pecks because a seed is present; a ball causes a ball-kicking action in a child).

Classic Behavioral Research: Puzzle Boxes and Instrumental Conditioning

• Edward Thorndike’s puzzle boxes (early 1910s) investigated problem solving in cats to test two views:
  • Insight learning: a sudden realization leads to rapid solution once the insight occurs.
  • Trial-and-error learning: gradual improvement as the animal repeats responses that lead to satisfaction.
• Thorndike’s method: place a hungry cat in a box with a mechanism to escape; measure escape time across trials.
• Predictions:
  • Insight view: initial trials slow (no insight), then a sudden jump to quick escape after insight, with rapid repetition thereafter.
  • Incremental view: gradual improvement as S-R associations strengthen through reinforcement; escape times decrease steadily and eventually plateau.
• Results favored gradual, incremental learning for Thorndike’s cats.
• Instrumental conditioning (later renamed operant conditioning by B.F. Skinner): learning is driven by the consequences of behavior; reinforcement strengthens S-R associations, punishment weakens them.
• Note on terminology: calling instrumental conditioning a form of trial-and-error learning is technically inaccurate because hypotheses (mental hypothesizing) are not part of behaviorist explanations.

Maze Learning: T-Maze and S-R Associations

• Simple apparatus: the T-maze, where a rat at the base of a T chooses left or right at the decision point; different goals have different outcomes (reward or nothing).
• Across trials, the number of incorrect choices decreases and correct choices increase, reflecting learning.
• Behaviorist interpretation of the T-maze:
  • Stimuli present at the start box become associated with responses (S-R links).
  • Each response brings the animal into contact with new stimuli; learning is the strengthening or weakening of these S-R links based on reinforcement or punishment.
  • A rewarded outcome strengthens the most recent S-R link; a nonrewarding outcome weakens it.
• Core takeaways about learning from these paradigms:
  • Learning is gradual and involves strengthening or weakening of S-R associations.
  • A response must occur for learning to take place (no learning with S alone).
  • Reinforcement (reward) is essential for strengthening associations; punishment (annoyance) has less central role in many analyses.
• Historical impact: 50 years of behaviorism as the dominant paradigm in American psychology, shaping numerous theories and methods.

The Rise, Dominance, and Decline of Behaviorism

• Behaviorism dominated American psychology for roughly five decades, with Pavlovian and Thorndikean learning as central foci.
• While some regions outside the United States did not fully adopt behaviorism, learning theory remained influential in the field.
• Limitations and challenges to the S-R framework accumulated over time, setting the stage for a cognitive turn in psychology.
• The next lecture in the course supposedly covers major difficulties that challenged behaviorism and contributed to its decline, enabling cognitive approaches to rise.

Connections, Implications, and Real-World Relevance

• Epistemology and foundational ideas:
  • The shift from nativist and rationalist explanations to empiricism aligns with the scientific emphasis on observable data.
  • The mind–body problem remains a central philosophical challenge for theories that aim to link neural processes with mental states.
• Methodological implications:
  • Early introspection aimed to quantify mental contents, but faced reliability and objectivity concerns, which contributed to the rise of behaviorism.
  • The emphasis on observable behavior laid groundwork for rigorous experimental methods and operational definitions.
• Theoretical implications:
  • Structure of scientific psychology moved from studying the structure of consciousness to studying the functions and laws of behavior.
  • The four axioms of behaviorism helped establish psychology as a natural science focused on objective data and generalizable principles.
• Ethical considerations (implicit): a shift toward objectivity and behavioral measurement raises questions about the treatment of animals in research and the translation of animal research to human behavior.
• Foundational links to later cognitive science: the decline of strict behaviorism created space for cognitive explanations that consider mental representations, information processing, and internal symbolic structures.

Key People and Concepts to Remember

• Wilhelm Wundt: founder of the first psychology laboratory (1879); view of psychology as the science of mental experience; two-step program (elemental analysis and laws of combination).
• Structuralism (Wundt, Titchener): identify basic conscious elements; introspection as a primary method; claimed thousands of elements.
• Functionalism (James, Angell, Dewey): focus on function of mind, stream of consciousness, adaptive role of mental processes; influenced by Darwin.
• James and functionalism: mind as an adaptive organ; emphasis on problem-solving and real-world usefulness.
• Behavioralism (Watson): psychology as objective science of behavior; rejection of mentalism; reflex arc as guiding concept; emphasis on S-R learning and reinforcement.
• Classical conditioning (Pavlov) and instrumental/operant conditioning (Thorndike, Skinner): two major learning processes explaining how associations form and behavior is shaped by consequences.
• Key laws and formulas:
  • Weber’s Law: $\Delta R/R = k$
  • Fechner’s Law (Weber–Fechner): $S = k \ln I$
  • JND: Just-noticeable-difference (definition in experimental context)
• Core vocabulary: introspection, contiguity, similarity, frequency, S-R (stimulus–response) associations, SR (reinforcing stimulus), reinforcement, punishment, instrumental conditioning, operant conditioning.
• Major experimental paradigms: puzzle boxes (Thorndike), maze learning (T-maze) with goal boxes, and simple operant conditioning setups (e.g., pigeons with pecking and reward systems).
• Broad historical arc: from philosophy and physiology to psychophysics, from introspection to behaviorism, and toward cognitive approaches in subsequent decades.

Important Formulas and Numerical References

• Weber’s Law: $\Delta R/R = k$
  • R = initial stimulus intensity; \Delta R = change needed for a JND; k = property-specific constant.
• Fechner’s Law: $S = k \ln I$
  • S = perceived quality; I = stimulus intensity; k = constant.
• Just-noticeable-difference (JND): the minimum detectable change in a stimulus.
• Typical experimental details mentioned:
  • Time frame in Thorndike’s puzzle boxes: 200 seconds per trial as an upper limit for recording escape time.
  • The focus on observable, publicly measurable data rather than private mental states.

Quick Connections to Foundational Principles and Real-World Relevance

• The early emphasis on observable behavior set a standard for objectivity in psychology, influencing experimental rigor and measurable outcomes.
• The mind–body problem highlighted the need to reconcile subjective experience with objective data, a tension still relevant in contemporary cognitive neuroscience.
• The shift from mentalism to behaviorism foreshadowed later debates about the role of internal cognitive processes and representations in explaining behavior.
• The historical progression shows how scientific disciplines evolve: from introspective, content-focused approaches to behavior-focused models, then toward information processing and cognitive theories that integrate internal states with observable behavior.