PSY 3360 Historical Perspectives on Psychology: Mind and Machines Since 1600 Study Guide for Midterm II – Fall, 2018
Lecture 6 Lecture 10
Hermann von Helmholtz (18211894)
Contributions in physics (mechanics & electromagnetism) and psychology (vision & audition)
Two main contributions in sensation & perception:
∙ Color vision – used color mixing experiments to determine that there are three kinds of color sensitive receptors (cones) in the retina
∙ Speech perception – discovered the sensory code for vowel perception TriChromatic Theory of Color Vision
∙ Extended Maxwell’s colormixing experiments showing that a color match (in hue, saturation, & brightness) can be produced with just three “primary” colors
∙ From this Helmholtz reasoned that there must be three kinds of color receptors in the retina
∙ Newton had demonstrated that a ray of sunlight could be split apart into its component wavelengths into a spectrum containing a rainbow of hues from blue violet (short) to red (long).
∙ Thomas Young and James Clerk Maxwell used what is now called a
“monochromator” to project narrow slices of the spectrum separately on a screen.
∙ They found that by making additive combinations of red, blue, & green they could produce any desired color (a procedure called “colorimetry”).
In the experiments we mix monochromatic wavelengths (pure colors) in one patch of light so as to match an arbitrarily selected sample in the other patch of light:
Don't forget about the age old question of What is the ionic basis for the resting membrane potential?
The three primaries don’t have to be red, green, & blue; they can be any three wavelengths as long as mixing two of them can’t produce the hue of the third. (I.e., they have to be wellspaced out along the spectrum.)
Helmholtz (18211894) continued
Audition: the sensory code for vowel sounds
∙ Sound consists of pressure waves in the air that travel at around 1100 ft/sec. ∙ The simplest sound is a sine wave (“pure tone”) and has just one frequency:
∙ The sine wave’s pitch corresponds to its frequency, and its loudness corresponds to its amplitude (intensity).
∙ We can represent the sine wave as a waveform or as a spectrum (a translation called Fourier Analysis).
Many sounds in speech and music consist of harmonic complex tones which are formed by a series of sine waves whose frequencies are integer multiples of a fundamental frequency (f0).
Helmholtz discovered that the timbre of vowel sounds (which makes “ah” and “oh” and “eeh” … different from each other) depends on the relative intensity of their various harmonics. If you want to learn more check out What is the valence shell electrons pair repulsion model (vsepr)?
The peaks in the spectrum envelope are called “formants.”
The receptors in the Organ of Corti would send a message to the brain coded in terms of the place of stimulation on the Basilar Membrane – a Place Theory of Vowel Perception. The vowel could be identified from the pattern of formants.
From further studies in the last 150 years we know that this is how it actually works.
The one point on which Helmholtz was wrong is that the Basilar Membrane does not consist of separate fibers. It is tightly connected like a fabric. Don't forget about the age old question of How did kepler challenge the earth centered model?
We also discuss several other topics like What is the purpose of heuristics?
Unconscious Inference – for example, the “moon illusion”
∙ Size constancy and size-distance trade-offs
∙ If two stimuli project the same size image on the retina, the one that’s farther away must actually be larger
∙ Conscious inference being overlaid on the unconscious inference, because we say to ourselves, “If it looks so large, it must be really close!”
Charles Darwin (18091882)
On the Origin of Species (1859)
Theory of Natural Selection – mechanism: blind variation & selective retention
∙ Some variation is relatively random, some builds on what’s already there – the important thing is that it’s blind (ie, it doesn’t know what the result will be)
∙ The variations are tested against the environment, and unsuccessful ones are weeded out. Examples: finches, perceptual systems
∙ In people: lactose tolerance in European adults, highaltitude adaptation in Tibet.
Social Darwinism was thoroughly discredited throughout the first part of the 20th century, but now seems to be regaining popularity among those who believe that the financially successful are naturally “fitter” than the poor (“losers” & “takers”). We also discuss several other topics like Why was the american revolution considered a process instead of an event?
Dennett has developed an argument showing how free will can be compatible with a deterministic universe.
Even if we lived in a clockwork universe (which we don’t), there would be events that will affect the outcomes of our decisions that we cannot (in principle) know about: our past, now, and future.
We have to make a decision in the here and now. We just hope we can make the decision free of constraint, so that we choose what we think is best for us. This is the kind of free will that in Dennett’s mind is worth having (unlike Descartes’s kind).
Charles Sanders Peirce (18391914)
On the Fixation of Belief: we search for answers and stop when we find what works well enough for present purposes.
In a community of searchers, this leads to a closer and closer approximation to the truth. But we never achieve the absolute Truth – “fallibilism”
Semiotics: the theory of signs is central to Peirce’s thought. We also discuss several other topics like What characterizes algorithmic functions?
∙ Icon – sign resembles thing signified (eg, a map or diagram)
∙ Index – sign indicates thing signified (eg, thunder & lightning)
∙ Symbol – sign is bound up in a system of other signs (eg, words in a language, or a theory in physics)
Categories: Like Kant, Pierce develops a set of categories – things we can know before we go out and observe anything.
∙ Firstness – what we have with a thing or a sign
∙ Secondness – what we have with a thing related to a sign
∙ Thirdness – what we have when a third entity (the interpretant) takes account of the relation of the sign and the thing signified
Peirce added a third kind of process for scientific investigation:
∙ Induction – bottomup
∙ Abduction – middleout
∙ Deduction – topdown
Before we can build an entire inductivedeductive framework we need to start in the middle ground we abduct, and work outward
For Peirce, there is not a onesizefitsall scientific method, but the various sciences have particular methods that work particularly well with the domain they are investigating.
Dispute with James: the “pragmatic criterion of truth” – for Peirce truth is determined by a community of serious investigators (vs just something that’s beneficial for an individual to believe).
After they both died the mainstream returned to being called “pragmatism.” Lecture 10
William James (18421910)
“stream of consciousness” – James’s wellknown label for the interconnected series of thoughts that make up our mental life
JamesLange theory of emotion –
∙ based on the notion that we have a fastreaction system that gets our nervous system going in response to stimuli, before we have a chance to process the incoming information thoroughly. Following the fast reaction, our cognitive systems gradually catch up.
∙ For example, we find ourselves hurtling down a forest path, and then we realize that a bear jumped out from behind a bush and made us afraid.
∙ This theory is essentially true but needs a correction:
∙ James believed that we could read internal signals associated with our fast reaction (that is, autonomic nervous system – ANS – responses) in order to understand what emotion we are feeling. This doesn’t work very well.
∙ Rather, we rely on context to fill in the cognitive components of emotion. This is shown in an experiment by Schachter & Singer (1962)
∙ Schachter & Singer gave Ss epinephrine (which causes an immediate ANS arousal) but led them to believe that it was a slowacting drug and that they should wait in the waitingroom until it would act and they could continue the experiment. They waited along with a confederate of the experimenter who acted out one or another emotional reaction (anger or euphoria). The Ss who received the epinephrine tended to fall in with the mood of the confederate, whereas those who received a placebo didn’t.
∙ This suggests that the ANS arousal can operate independently of the context that provides the cognitive interpretation of the emotion.
The Rise of Radical Behaviorism
In the early years of the 20th century, John B. Watson started a movement that would dominate American psychology for 50 years: Behaviorism
The Radical Behaviorists believed that psychology should only concern itself with publicly observable events – stimuli and responses – and avoid introspection and theorizing about mental events
They seized control of the major journals and academic departments, vigorously imposing their point of view
Factors leading to the rise of Radical Behaviorism:
The crisis of introspection
An existing repertoire of behavioral methods + popular success of Pavlov The influence of natural science
∙ Success and prestige
∙ Model of how science should operate: publicly observable phenomena + material monism