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PSY 3360 / CGS 3325Historical Perspectives

on PsychologyMinds and Machines since 1600

Dr. Peter Assmann

Spring 2020

Important dates

• Feb 19– Term paper draft due

– Upload paper to E-Learning https://elearning.utdallas.edu

• March 2 – Midterm Exam– Optional extra credit: Midterm review benefit

Midterm Exam Review Benefit

• Extra credit assignment

• Due Monday March 2 (same date as midterm exam)

• Upload to E-Learning

• Instructions online:

http://www.utdallas.edu/~assmann/PSY3360/midterm_exam_review_benefit.html

Immanuel Kant (1724 –1804)

“Some birds fly south in

winter”

Kant’s categories;

mathematics

synthetic

(none)“Triangles have three sides”analytic

a posterioria priori

“Some birds fly south in

winter”

Kant’s categories;

mathematics

synthetic

(none)“Triangles have three sides”analytic

a posterioria priori

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“Some birds fly south in

winter”

Kant’s categories;

mathematics

synthetic

(none)“Triangles have three sides”analytic

a posterioria priori

Key concepts• Kant regarded mathematics as synthetic a priori

because it depends on the pure intuitions of the elements of time and space.

Kant's categories• Kant’s categories include the most general

concepts of human experience.• These provide a conceptual framework in

terms of which all objects are analyzed.• The objects of empirical knowledge

(everything we experience) is “filtered” through the categories.

Critique of Pure Reason

• Transcendentalism: philosophical view that there is a form of knowledge derived from synthetic a priori judgments.

• Objects in the real world are fundamentally unknowable. They provide the raw material from which sensations are derived.

Noumena and phenomena

• Noumena: “things-in-themselves”–objects in a pure state independent of human experience; cannot be known directly.

• Phenomena: anything experienced is transformed by the mind into a subjective phenomenon (i.e., conditioned by space, time and the categories).

Ethical and moral philosophy

• The categorical imperative is the basis of morality and was stated by Kant in these words: "Act as if the maxim of your action were to become through your will a general natural law."

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Kant’s theory of causality

Hume's rejection of causality

Co-occurrence of events

Habitual association

(Illusory) feeling of necessity

Kant’s answer: Causality is fundamental to science and human knowledge

a relationship not based on observation or logic

imposed by the structure of the human mind

Kant’s psychological theory

Noumena and phenomena

Space, time and the 12 categories of

experience

Perception is an active process

The mind actively participates in the

construction of reality

Kant’s theory of causality

Hume's rejection of causality

Co-occurrence of events

Habitual association

(Illusory) feeling of necessity

Kant’s answer: Causality is fundamental to science and human knowledge

a relationship not based on observation or logic

imposed by the structure of the human mind

Kant’s contributions to psychology

Synthesis of empiricism and rationalism

Perception is an active process

The mind makes an active contribution to our experience of reality

The mind can be studied, but only by introspection, not direct observation.

Kant’s contributions to psychology

Kant believed that mental phenomena could

not be studied empirically because they

(1) lacked spatial dimensions

(2) were too transient

(3) could not be experimentally manipulated

(4) could not be described mathematically.

19th century developments: Germany

• Increased interest in sensation and perception

• New, emerging view of the relationship between mind and body: – higher cognitive functions are mediated by the central

nervous system.

– perception can be measured and mapped out using methods developed in other branches of science.

– the idea of a threshold: the minimum amount of energy required to elicit a change in perception.

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Emerging viewpoints

1. Higher cognitive functions are mediated by the central nervous system.

2. Sensation and perception can be measured and mapped out using methods developed in other branches of science.

3. Concept of a threshold, the minimum amount of energy needed to elicit a change in perception.

4. Elaboration of the laws of association.

Hermann Ludwig Ferdinand von

Helmholtz (1821-1894)

Hermann Ludwig Ferdinand von Helmholtz (1821-1894)

• Life and times

• Medicine, physiology, mathematics, physics

• Rationalism and empiricism

• Vitalism and mechanism

Vitalism vs. Mechanism

• Vitalism: living things share a vital

force that cannot be explained by

the physical sciences (Müller)

• "Willed behavior is instantaneous."

• Mechanism: same laws apply to

living and non-living things

(Helmholtz)

• Principle of conservation of energy

Johannes Müller1801-1858

Helmholtz’ studies of nerve conduction

Measured speed of nerve conduction using a modified galvanometer

• Mild electrical stimulation of a frog’s leg produces muscle twitches.

• Conductance rate: ~90 feet/sec

Speed of nerve conduction

• Reaction times in humans: subjects pressed a button in response to tactile stimulus

Response times ~165-330 feet per second

Nerve transmission rate is finite (relatively slow)

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Helmholtz' theory of perception

• Perception = active, unconscious, automatic, logical processes

• Unconscious inference• Role of learning and memory in

transforming sensory information

– Experiments with distorted lenses– Motion pictures– succession of still

images– Railroad tracks are parallel but seem

to converge in the distance

Visual Perception Perceptual Adaptation—The idea that when one’s visual field is altered (e.g., when images are shifted to the left or right from their normal locations while wearing special glasses), one’s brain adapts to new perceptions automatically and unconsciously.

Visual Perception Unconscious Inference—According to Helmholtz, the idea that perceptual adaptation and other perceptual phenomena might result from a process in which there is an unconscious adoption of certain logical rules.

Young-Helmholtz theory of color vision

• Newton (1672) – wavelength

• Trichromatic theory: human color vision involves three color receptors (RGB)

• Color receptors (cones) in the retina

• Laws of color mixing

• Color blindness

Munsell color system

Hue: dominant wavelength

Value: brightness

Chroma: purity

Color Vision Color Mixing—The phenomenon studied by Maxwell and others, showing that varying mixtures of spectral light can produce the same color sensations as pure spectral colors.

James Clerk Maxwell (1831‐1879)—A Scottish scientist who studied color vision and who provided the most complete analysis of color mixing in 1855.

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Complementary Colors—Pairs of spectral colors (e.g., red‐green and blue‐violet) that, when mixed together, create a sensation of white light indistinguishable from sunlight.

Primary Colors—The spectral colors red, green, and blue, which are the building blocks for all of the kinds of color sensation.

Thomas Young (1773–1829)—An English scientist who, like Helmholtz, suggested that the retina contains three types of receptor cells necessary for color vision.

Young‐Helmholtz Trichromatic Theory—Idea proposed by Thomas Young and Hermann von Helmholtz suggesting that there are three types of receptor cells in the eyes, each one responding to a different spectral hue, making color vision possible.

Auditory theoryHelmholtz proposed that the cochlea, part of the inner ear, is responsible for frequency analysis in hearing.

Theory of hearing Helmholtz proposed that the basilar membrane, housed

within the cochlea of the inner ear, responds selectively to the different frequency components of sound waves.

high frequencies

low frequencies

Place (resonance) theory of hearing

• Cochlear fibers vary in length

• Tuned to vibrate at specific frequencies

• Different positions along the cochlea respond selectively to different frequencies to determine what pitch we hear

Frequency analysis• Fourier analysis: mathematical

decomposition of any complex waveform into simple sinusoidal components

Joseph Fourier(1768-1830)

Complexwave

Simplesine

waves

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Frequency analysis• Fourier synthesis: any complex waveform

can be reconstructed (synthesized) from sine waves.

Joseph Fourier(1768-1830)

Vowelsound

Simplesine

waves

Response to a low-frequency sound

Response to a high-frequency sound Frequency and pitch

• Physical property: Frequency

• Psychological property: Pitch

Sine wave Complex wave

On the sensations of tone

Helmholtz invented the double siren to produce tones of any specified frequency.

He used this device to map out the mathematical relationship between frequency and pitch.

Frequency and pitch

• Physical property: Frequency

• Psychological property: Pitch

Sine wave Complex wave

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Musical tone

“First of all, what is a musical tone? Commonexperience teaches us that all soundingbodies are in a state of vibration … Thesound becomes a musical tone, when suchrapid impulses recur with perfect regularityand in precisely equal times. Irregularagitation of the air generates only noise. Thepitch of a musical tone depends on thenumber of impulses which take place in agiven time; the more there are in the sametime the higher or sharper is the tone.”Helmholtz, 1865

Pitch Perception

Helmholtz proposed that the location (place) of maximum vibration along the basilar membrane determines the pitchwe perceive.

Frequency

Inte

nsity

Sine wave

Pitch Perception

Complex sounds have many components; the activation produced by the lowest one (called the fundamental frequency) determines the pitch.

Frequency

Inte

nsity

Complex wave

Frequency analysis

Frequency Frequency

Inte

nsity

Inte

nsity

Sine wave Complex wave

Problem of the missing fundamental

100 200 300 400Frequency (in cycles/sec, or Hz)

Helmholtz proposed that nonlinear interaction in the cochlea re-introduces the missing fundamental. (We now know this hypothesis was incorrect).

Original

Missing fundamental