1. Kant's Objections to Psychology
The mind wasn't a physical entity
The mind could not be objectively observed since it was always changing and introspection would always reveal the mind in the process of introspecting itself
The mind could not be subjected to mathematical descriptions and formulations

2. Kant's Objections to Psychology
The mind wasn't a physical entity
The mind could not be objectively observed since it was always changing and introspection would always reveal the mind in the process of introspecting itself
The mind could not be subjected to mathematical descriptions and formulations

3. Kant's Objections to Psychology
The mind wasn't a physical entity BUT Helmholtz measured the speed of the nerve impulse and other aspects of the physical basis of thought
The mind could not be objectively observed since it was always changing and introspection would always reveal the mind in the process of introspecting itself BUT Donders invented the reaction time methodology which provided objective measures of the functioning of other minds
The mind could not be subjected to mathematical descriptions and formulations BUT Weber and Fechner came up with precise mathematical expressions that related the intensity of a physical stimulus (like light) to the magnitude of the subjective sensory impression it produced (perceived brightness)

4. Some Precursors to Psychology
Johannes Müller c.1826
Doctrine of Specific Nerve Energies
Hermann von Helmholtz c.1850
rate of nerve conduction: 50 m/sec
perception as "unconscious inference"
theories of color vision, hearing
Ernst Weber c.1840
perceptual judgements are relative, not absolute
Gustav Fechner c.1860
"psychophysics": absolute difference in psychological experience is proportional difference in physical stimulus
Franciscus Donders c.1865
subtractive logic in reaction time studies

5. Doctrine of Specific Nerve Energies
(Johannes Müller, 1826)
quality of sensation (visual, auditory, touch, etc.) depends on which nerve fibers are stimulated - NOT on the stimulus itself
fibers of optic nerve are normally stimulated by light
- may also be stimulated by pressure, electric current, and so on
- any stimulation will yield experience of light
any sensory experience must have corresponding set of nerve fibers: experiences of brightness, color, loudness, pitch, etc.

6. 5:2

8. Fig. 5.28

10. Some Precursors to Psychology
Johannes Müller c.1826
Doctrine of Specific Nerve Energies
Hermann von Helmholtz c.1850
rate of nerve conduction: 50 m/sec
perception as "unconscious inference"
theories of color vision, hearing
Ernst Weber c.1840
perceptual judgements are relative, not absolute
Gustav Fechner c.1860
"psychophysics": absolute difference in psychological experience is proportional difference in physical stimulus
Franciscus Donders c.1865
subtractive logic in reaction time studies

12. HELMHOLTZIAN PROGRAM
monocular depth cues (only one eye needed):
- linear perspective - convergence point is far away
- interposition - nearer objects will occlude (block) farther objects
- relative size - nearer objects cast larger retinal images than farther objects (of same size)
"unconscious inference"
- best guess at what DISTAL stimulus PROBABLY caused the PROXIMAL stimulus (the retinal image)
- perception is always in the direction of the best inference ("maximum likelihood")

13. infer distance of object:
- learned: points nearer to where lines converge are farther away
- retinal image: object appears near to where lines converge (linear convergence cue)
- infer: DISTAL object must be far away
use this inference to get SIZE information:
- learned: far off objects produce smaller retinal images
- retinal image: two objects appear to have SAME retinal image size (relative size cue)
- infer: the farther-away DISTAL object must be LARGER

15. Page 235

17. Some Precursors to Psychology
Johannes Müller c.1826
Doctrine of Specific Nerve Energies
Hermann von Helmholtz c.1850
rate of nerve conduction: 50 m/sec
perception as "unconscious inference"
theories of color vision, hearing
Ernst Weber c.1840
perceptual judgements are relative, not absolute
Gustav Fechner c.1860
"psychophysics": absolute difference in psychological experience is proportional difference in physical stimulus
Franciscus Donders c.1865
subtractive logic in reaction time studies

18. PSYCHOPHYSICS: relation of physical variables of environment to sensations in our experience
How is intensity of light related to our experience of "brightness"?
to be detected, intensity must exceed the absolute threshold
- for a change to be detected, intensity must increase by the difference threshold

19. "just noticeable difference" (j.n.d.):
light of intensity I increased by∆I notice? NO NO NO NO
YES!

20. Weber's Law (1834): ∆I / I is constant
∆I / I = change in intensity relative to original intensity
- for I = 60, ∆I = 1
- for I = 120, ∆I = 2
- for I = 180, ∆I = 3
so for vision, ∆I / I = 1/60: "Weber fraction"
- smaller Weber fraction means greater sensitivity
- hearing is less sensitive: ∆I / I = 1/10

21. Table 5.1

22. Fechner’s Law (1860):
coined the term “Weber’s Law” for ∆R / R = k
the ratio of change in stimulus intensity to original stimulus intensity is a constant
R is “Reiz”, German for “stimulus”; ∆R is the “just noticeable difference” or “jnd”; the constant “k” is specific to a sense modality, e.g., vision, hearing, comparing lifted weights
then “Fechner’s Law” said more generally S = k * log R
“S” is the intensity of the sensation experienced, “log R” is the logarithm of the stimulus intensity, “k” is the constant relating them for a given sense modality (vision, audition, etc.)
logarithms are exponents, so the sensation becomes arithmetically or linearly stronger as the stimulus intensity gets exponentially stronger
still recognized today, though modified for extreme values by S.S. Stevens in 1957

23. Some Precursors to Psychology
Johannes Müller c.1826
Doctrine of Specific Nerve Energies
Hermann von Helmholtz c.1850
rate of nerve conduction: 50 m/sec
perception as "unconscious inference"
theories of color vision, hearing
Ernst Weber c.1840
perceptual judgements are relative, not absolute
Gustav Fechner c.1860
"psychophysics": absolute difference in psychological experience is proportional difference in physical stimulus
Franciscus Donders c.1865
subtractive logic in reaction time studies

24. Donders’s reaction time method and subtractive logic (1869):
SIMPLE reaction time: respond to stimulus (such as a light) with a predetermined response (such as pressing a button)
DISCRIMINATION reaction time: respond to only one of several different stimuli A B C D E (e.g., only to stimulus C)
- discrimination time = discrimination reaction time minus simple reaction time
CHOICE reaction time: make different response so each of several different stimuli (e.g., reponse “a” to simulus A, “b” to B, etc.)
choice time = choice reaction time minus both simple and discrimination reaction times
measured time course of mental operations but proved too variable, requiring 20th century statistics for data analysis
re-emerged in 1960s in cognitive psychology, as indirect measure of the processing demands implied by different models of cognition

25. Early Psychology Wilhelm Wundt c. 1879; d. 1920 (Leipzig)
voluntarism: emphasizes volition, attention, will, choice, purpose; more Locke than Hume
use reaction time, "experimental" introspection, etc. to replicate and extend earlier findings
first "paradigm" in psychology (in both senses)
only lower level processes studied in lab; higher processes studied through "Volkerpsychologie"
examine religion, customs, history, language, morals, art, law, etc. to reveal higher thought processes
elements of thought organized by LAWS, but not empiricist laws of association

26. Early Psychology Edward Titchener c. 1899; d. 1927 (Cornell)
"structuralism": emphasizes static elements of consciousness - structure, not function
study consciousness (mental experience at a moment); mind was the lifetime accumulation of experience
used introspectors trained to avoid the "stimulus error"
catalog sensations and their laws of combination -- mainly association by contiguity
eventually "discovered" 40,000 sensations (30,000 visual, 12,000 auditory, 20 other)
all thought was image-based
ignored: applications, animals, abnormality, personality, development, individual differences, evolution

27. Early Psychology Oswald Kulpe c. 1894; d. 1915 (Wurzburg)
Imageless thoughts arose in context of judgements about "heavier than" or "lighter than"
ex.: no images accompanied thoughts of search, doubt, confidence, hesitation
Titchener et al debated this issue, : arguments about who was doing introspection better, more accurately, more reliably
till finally…
John Watson (1913)
"Psychology as the Behaviorist Views It"

28. John Broadus Watson (1913): Psychology as the Behaviorist Views it
John Broadus Watson (1913): Psychology as the Behaviorist Views it. Psychological Review, 20, ; first paragraph:
"Psychology as the behaviorist views it is a purely objective experimental branch of natural science. Its theoretical goal is the prediction and control of behavior. Introspection forms no essential part of its methods, nor is the scientific value of its data dependent upon the readiness with which they lend themselves to interpretation in terms of consciousness. The behaviorist, in his efforts to get a unitary scheme of animal response, recognizes no dividing line between man and brute. The behavior of man, with all of its refinement and complexity, forms only a part of the behaviorist's total scheme of investigation.”
rats running in mazes objectively make a certain number of wrong turns and objectively take longer or shorter times
use of conditioning (not yet differentiated into classical and operant)

29. Early Psychology Functionalism
influenced by William James and Darwinian evolutionary theory, which assumed mind had a function useful to an animal's survival
opposed to structuralism: instead of understanding elements and structure of mind through introspection, study how mind and behavior better adapt an organism to its environment
interested in both mind and behavior -- so methods included introspection, but also puzzle boxes, mazes, mental tests, etc.
studied animal behavior as well as special human populations (children, mentally ill)
interested in practical applications (in self-improvement, education, industry, etc.) as well as theorizing
interested in motivation of behavior, whereas structuralism didn't depend on motivation
interested in individual differences (e.g., in intelligence, motivation, etc.), instead of solely focusing on universal characteristics of mind