Physiology
Bell-Magendie Law – sensory nerves carry
information forward to the brain, and motor
nerves carry information from the brain to the
body.
Johnnes Muller – had doctrine of specific nerve
energies --- each nerve carries a specific type of
energy no matter how it is stimulated……no
matter the stimuli, the nerve is going to send the
same type of information it is designed to convey.
Hermann von Helmholtz (1821-1894)
---last pure scientists….knew everything about
everything
---empiricist….experimentation and observation
----opposed vitalism---the belief that life was
“more than” a physical process.
---published a proof of the Law of Conservation of
Energy (energy is never created or destroyed, but
merely transformed.….applied it living organism
---measured the rate of nerve energy
transmission…..important b/c it showed again
that body processes could measured and it wasn’t
some process outside the realm of science.
---Theory of perception…..sensations are stimuli,
but perceptions are our interpretation of stimuli
based on past experience (memory)….idea
supplants Kant’s innate categories of the mind
(not born with them, but learn them over time).
---Young-Helmholtz theory of color vision—(trichromatic theory)…..three separate receptors for
color vision….not just one receptor or nerve
energy….expanding on Muller’s idea of specific
nerve energy to 3 types of nerves in the eye.
--Auditory perception ---resonance place theory –
specific nerves in the ear respond best to specific
frequencies of sound.
Franz Joseph Gall (1758-1828) –neuroanatomist
who linked behavior to physical features….called
it the study of “organology”
--felt that cranial features correlated with mental
abilities…..
---Phrenology------did impact science b/c it
popularized the idea of mind and brain are
related, that specific areas of the brain related to
specific behavior.
Weber (1795-1878)---physiologist studying senses
of touch and kinesthesis (muscle sense).
---notable b/c most research was limited to
auditory and vision, but he studied other senses
like touch (skin) and muscle sensation.
--came up with the two-point threshold--- smallest
distance subjects can report two pin-pricks
instead of one.
---Weber’s law – JND’s correspond to a constant
fraction of a standard stimulus.
….first quantitative law in
psychology……judgments are not absolute…and
not a 1 to 1 correspondence with reality….
….JND (just noticeable difference)—threshold for
perception
Gustav Fechner (1801-1887)
Father of Psychophysics….the study of the
relationship between physical and psychological
events.
F=M*A
A = F/M
Derived a formula for the expression of stimuli’s
effect on sensation……the formula states that
stimuli must increase geometrically to have an
additive effect on sensation……that is, as
stimulation increases, larger and larger increases
are needed to affect sensation. S = k log R
R
k
R
Did a lot of work on the thresholds of sensation.
Absolute threshold – minimum stimulation needed
to be detected by the senses.
Difference threshold ---how much a stimulus
magnitude needs to be increased or decreased
before you can detect the difference.
Psychophysical methods –
method of limits – one stimuli is varied while
being compared to a constant stimuli----find range
of stimuli equal to the standard
Method of constant stimuli---two stimuli
presented and one varies….find whether the
variable stimuli is the same, less, or greater than
standard.
Method of adjustment----a person varies a
stimulus to equal a standard.
Voluntarism
Wilhelm Wundt (1832-1920) – Founding of
psychology as a science……established first
research lab in Leipzig in 1879.
---wedded physiology and philosophy and the
result was something different than the
two….brought empirical methods of physiology to
the question of philosophy
Important to Wundt is the concept of “will”…..we
decide what to attend to and not…..
Introspection as a methodology to study the
contents on the mind…..not philosophical
introspection, but structured introspection