Those who do not know the history of their field are doomed to repeat its mistakes (Santayana).

1/18/01


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Those who do not know the history of their field are doomed to repeat its mistakes (Santayana).

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FUNCTIONALISM Darwin: Structures are adaptive because they assume a certain function. -Search for structure can be facilitated by studying function. -Structure can be inferred from function, e.g., research in physiological psychology. William James: What is the function of consciousness? That topic is central to modern psychology.

PRE-GREEK ZEITGEIST People observed alternations of rhythms: day and night, seasons, famines, etc. Awareness and recall of dreams: images of dead people, animals, composites. Concerns about the nature of things, - Cosmologies devised as explanations. Motivation for cosmologies was not scientific, e.g., predicting eclipses, droughts, etc. That was engineering, not science. Cosmologists formulated hypotheses about the basic units of things: - water, fire, air, earth, numbers. Pythagoras is a well known example. He believed that numbers held the secret of everything.

REDUCTIONISM Democritus was the first cosmologist to attempt to explain things by reductionism. In about 400 BC, Democritus postulated that atoms were the basic unit of all matter and that there were two types of atoms: - body atoms (inert) - soul atoms (vital substance) Democritus is also credited with introducing the mind-body distinction.

DYNAMIC VS. RELATIONAL COSMOLOGIES: Dynamic (Heraclitus): Things are always in flux. Consciousness is never the same at successive points of time. -A basic problem for all sciences: how do static units change over time? Relational (Anaxagoras): It is not meaningful to talk about elementary units without specifying their organization. The whole is greater than the sum of its parts.

REACTIONS TO COSMOLOGIES How do we know about reality? -Through senses? -Are the senses trustworthy? Epistemology: What is the nature of knowledge? Sophists: There is no absolute knowledge. We only know what our senses tell us.

Plato (Socrates?) & Aristotle Plato: Rejected relativism of Sophists and sharpened the mind-body distinction: Reason supplements what we learn through sense organs and functions independently of the senses. The function of the soul is to apprehend ideal knowledge of the world through reason, to provide a means of going beyond the imperfect data of the senses and for defining the universals of beauty, goodness, mathematics, etc. (cf. Descartes, Kant, Chomsky). Aristotle: Defined the empiristic point of view [tabula rasa]. He did not accept the universals of knowledge that Plato postulated.

GREEK HERITAGE Dualism: mind vs. body - What is the nature of each entity? How do they interact? basic question of modern behavioral and cognitive psychology. Materialism vs. Idealism: -Materialists: everything is reducible to some physical entity. -Idealists: ideas exist independently of any material substance (Descartes, Kant, Chomsky) Nativism vs. Empiricism: -nativists: Knowledge exists independently of experience (knowledge may be material, e.g., brain states as postulated by modern theories of in neuroscience). -empiricists: Knowledge derives from experience. The empiricist view defines a basic question in the study of language, object recognition, etc. Behaviorists regard the concept of tabula rasa as basic.

Descartes Postulated two types of substance: 1. Material (body) extended substance: Extended matter occupies Newtonian space. 2. Soul (thinking) unextended matter: Unextended matter does not occupy Newtonian space. -Thinking matter, which is unique to man, is the seat of innate ideas. -Body and soul interact in the pineal gland (but do not reside there). -Animals, who have no souls are mere automatons: mechanical robot-like creatures. Two Cartesian heritages: -mechanical action (reflexes) -modern view of innate ideas--picked up by Kant & Chomsky.

CONCEPT OF REFLEX CONCEPT OF THE REFLEX Reflex: A correlation between a stimulus and a response. The stimulus releases the response, as pulling a trigger fires a bullet. *Animal spirits: flowed in hollow tubes from sense organ to muscles. *Glisson: Disproved the hypothesis of animal spirits by showing that excised muscle tissue contracts when stimulated (in a dish of saline solution). These experiments gave rise to the concept of irritability and excitability. *Concept of ìSpinal mindî: suggested by results of experiment on the magnitude of the flexion reflex in frogs whose spinal cord were severed (ìspinal preparationî) *Pfl¸ger: Inferred spinal mind because of variability in the magnitude of flexion reflex. *Magnus: Showed that variability was due to uncontrolled shifts in posture.

JOHN LOCKE Emphasized the basic role of experience: (cf. 1690 Essay concerning human understanding.) Resurrected Aristotle's concept of tabula rasa. How does tabula rasa get impressed? Introduced ideas as the basic unit of the mind and the concept of mental chemistry: how simple and complex ideas interact.

Mental Chemistry Simple ideas (sensations). Complex ideas (reflection, thought, perception). Ideas can have either of the following qualities: -Primary qualities: quantitative properties of an object (e.g., mass, motion, temperature, etc.). -Secondary qualities: in the "eye" of the beholder (qualitative differences: colors, sounds, tastes, etc.).

British School of Empiricism Berkely: claimed that all ideas were secondary in nature. God insures stability of world because He has primary ideas. Hume: Doubted existence of mind and God. All we have is a collection of ideas. What we must discover are the principles of association of those ideas (Aristotle), Hume proposed as principles of association (after Aristotle): resemblance, contiguity, and cause and effect (temporal succession). Hartley: Placed ideas in nervous system and hypothesized that they obey Newtonian laws. James Mill: All ideas are reducible to simple sensory elements.

Ronald Knox: There was a young man who said, God must think it exceedingly odd if he finds that this tree continues to be when there is no one about in the Quad. Reply: Dear Sir: Your astonishmentís odd: I am always about in the Quad and that is why the tree will continue to be since observed by Yours faithfully, God

RELEVANT DEVELOPMENTS IN BIOLOGY Reflexology Sensory physiology Theory of evolution

SENSORY PSYCHOLOGY Developed out of ancient concern to understand senses. Knowledge of sensory psychology was facilitated by: - assumption that the body obeyed mechanical laws. - advances in resolution of the microscope. - the discovery of nerves Bell and Megendie: Discovered independently the difference between sensory (dorsal) and motor (ventral) nerves. M¸ller: How many types of sensory nerves are there? Law of Specific Nerve Energies: Helmholtz: Hypothesized specific nerve energies for primary colors - red, green, blue. Gall: Phrenology.

TABLE OF SENSATONS eye 32,820 ear ? nose 4 tongue 4 skin 2 muscle 1 tendon 1 joint 3 alimentary canal ? blood vessels 1? lungs 1 sex organs 1 ear (static sense) 1 ------- Total: 44,435 (From E. B. Titchener ìAn Outline of Psychologyî, NY: Macmillan, 1896 pp. 74-75.

PSYCHOPHYSICS Sensory psychologists often asked subjects to make judgments. This gave rise to various mathematical generalizations about sensory function. Weberís Law: ¾I/I = K [DIFFERENCE THRESHOLD] I = Physical magnitude of stimulus ¾I = Physical magnitude of change needed to produce a just noticeable difference (jnd) K = constant Fechnerís Law: S = Klog I S = Subjective magnitude of stimulus I = Physical magnitude of stimulus K = constant Stevens Law: S = KIn S = Subjective magnitude of stimulus n = exponent whose value varies with sense modality K = constant I = Physical magnitude of stimulus

THEORY OF EVOLUTION Three aspects relevant to psychology: - Variation - Continuity of Structure - Functionalism

VARIATION Charles Darwin and his disciple Herbert Spencer, argued that the logic of variation and selection also applied to behavior. Note the similarity with respect to the logic of reinforcement theory. Galton: Observed that intellectual ability varied between individuals (just as structural features vary). -Asked how can variation of intellectual ability be measured? -Argued for sensory ability as a measure of intelligence. -Experiments on individual differences led to development of I.Q. and other psychological tests. -Assumed that intelligence is innate.

BEHAVIORAL ADAPTATIONS Examples of Continuity of Biological Structure: -eyes -breathing apparatus -digestive systems -camouflage -musculature Comparative psychologists ask, is there continuity of mental ability and consciousness between animal and man? Modern examples of continuity: a. instincts - study of ethology b. reflexes - conditioned & unconditioned reflexes Clever Hans Morganís Canon of Parsimony

Clever Hans

FUNCTIONALISM Darwin: Structures are adaptive because they assume a certain function. -Search for structure can be facilitated by studying function. -Structure can be inferred from function, e.g., research in physiological psychology. William James: What is the function of consciousness? That topic is central to modern psychology.

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 Author: Psychology Department

Email: jcesario@psych.columbia.edu

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