Midterm Flashcards
dualism
the idea that mind and body
are fundamentally different substances
or processes
Monism or Materialism:
The
universe is made of only one kind of
physical material (“atoms”)
de la Mettrie (1748)
“L’homme Machine”
People are machines with mechanical
systems plumbing, ventilation,
temperature control, etc.
Darwin (ca. 1850) :
all biological structures are “devices” that are adapted to serve the survival of the organism • -> The mind is a machine
What is a “machine?”
A machine is a process consisting entirely of
physical, material elements that affect each
other causally—that is, via physical processes. we reduce things we DON’T
understand to combinations of things we DO
understand.
mechanistic theory
every element is understood in terms of the
combination of simpler, stupider, elements.
homonculus
an imaginary “man
inside the head”
Syllogism
a chain of reasoning which the conclusion follows from the premises with logical certainty
George Boole:
An Investigation of the Laws of
Thought (1854)
•In algebra, we can make statements about numbers
that are true regardless of the specific values of the
numbers:
x + x = 2x
•Boole proposed to do the same thing with propositions
instead of numbers.
Propositions
Propositions are statements that are true or false.
Boolean algebra
a way of “calculating” with ideas instead
of with numbers, also called Propositional Calculus
logical connectives
how we put propositions together
conjunction
A∧B “A is true AND B is true”
disjunction
A∨B “A is true OR B is true (or both)”
negation
~A, “not A” = “A is not true”
implication
A → B, “If A is true then B is true”.
(Equivalent to ~(A∧~B), which is equivalent to ~A∨B ….
not really a separate connective)
Charles Babbage
1830 - Analytical Engine
Alan Turing
Wrote the basis for modern computing, he described a hypothetical computer called a Turing machine.
A Turing machine
A Turing machine gets input symbols on an infinite paper tape, and
writes output symbols on the same tape
It can:
• Read symbols to the tape
• Write symbols to the tape
• Move the tape left or right
• Make (logical) conditional decisions about which of the above to do.
algorithm
a concrete procedure to solve a particular problem
that is, give a particular output for each input
A universal Turing machine
is a Turing machine that can be given the encoding of
another Turing machine and “simulate” it
Turing test
Can a machine “think”?
or a better yet:
What observable behavior would count as thinking?
Church-Turing thesis
Anything that can be computed by any system can be computed by a
computer (a Turing machine)
Any process you can create an algorithm for can be carried out on a
computer.
Any process you can’t create an algorithm for — you don’t fully
understand.
Logic gates
Same as connectives,
but as a piece of a circuit
Neuron
Neuron integrates excitation and inhibition to get total net activation;
If activation is above threshold, it “spikes” (sends an action potential down the axon)
After firing, the neuron resets (~2 or
). If it is still being stimulated over threshold, it fires again. Hence the firing rate indicates the
level of activation.
McCulloch & Pitts:
Logical circuits and
artificial neural networks are equivalent
• You can make logic gates out of neurons
• You can make neurons out of logic gates
• Neural networks are computationally
equivalent to computers/Turing machines
• The brain is a giant computing device
Empiricism
(nurture) based on experience Blank slate/ Tabula Rasa Associationism Behaviorism General learning mechanism
Rationalism
(nature) based on reason innate knowledge Nativism Cognitivism domain-specific innate modules
Watson: Behaviorism
B. F. Skinner
Stimuli / Response All learning is conditioned responses to stimuli
Behaviorism
Mind starts as a blank slate
- Learn associations between behaviors and reinforcement
(reward) — i.e. stimulus and response
- Do more of the behaviors that are reinforced (Law of
Effect - Thorndike)
- Only mechanism of learning is modification of S-R pairings
• Implications of both behaviorism/empiricism
All knowledge comes from experience
- One general learning mechanism shared among all
domains of learning, all species, all ages - rats, children,…
Chomsky (1959)
argued that S-R reinforcement was mathematically
insufficient to explain behavior that involves an infinite number of
possible “responses”
Occipital lobe
vision
Temporal lobe
audition etc
Parietal lobe
attention etc
Frontal lobe
executive function, decision making
Broca’s area
responsible for speech, left hemisphere
A split-brain patient
Left hemisphere sees the RIGHT visual hemifield and controls the RIGHT arm Right hemisphere sees the LEFT visual hemifield and controls the LEFT arm
Contralateral:
opposite side
Ipsilateral
same side
Neuroimaging
brain scans
PET
positron emission tomography
fMRI
function magnetic resonance imaging
BOLD signal
Blood Oxygen
Level Dependent; shows where the blood
is going
veridical
(true) representation
constancy
A constancy is an apparent invariance of some property of the world despite enormous variation in the corresponding property in the visual image
shape constancy
Apparent shape
remains constant
despite changes in
3D pose
Lightness constancy
Apparent surface reflectance remains
constant despite changes in illumination
Color constancy
•Apparent surface color remains
constant despite changes in illuminant
color
Size constancy
Apparent physical size remains constant despite enormous
changes in retinal size as distance changes
Cones
3 types:
short, medium & long
wavelength
Rods
just 1 type, but more
sensitive, faster response
Fovea
central area of retina with high density of
photoreceptors, so high resolution. Mostly cones. The
fovea is what you point at something when you “look at it”
Periphery
low density of photoreceptors – mostly rods
Color
Physics: All light has a wavelength (=1/frequency). Pure
lights of different wavelengths appear different colors.
Note: All light is “colored”
Psychology: But there is more to color than wavelength.
- Most surfaces are mixtures of different wavelengths.
reflectance function
The reflectance function of a surface is a characteristic
of the surface, just like the reflectance of a surface.
What is the relative response of the 3 cone
types?
The brain infers the reflectance function from the ratio of
responses of the 3 types.
Opponent processes
Blue-Yellow, Red-Green,
(hue)Light-dark, (Saturation)
lateral inhibition
“Spot detector”
Perceptual grouping
Perceptual grouping is the organization of
the raw elements of visual image into
larger units, like contours, surfaces, and
objects.
Gestalt perceptual organization
“The whole is different from the sum of its
parts
Figure and ground
Each boundary separates one
region that is closer (figure)
and another that is farther
(ground)
Border ownership
The figural (blue) side of the boundary “owns” the
boundary, because
1. the figure actually ends there, while
2. the ground side continues behind the figure
Cells in Visual Area 2 (V2) are sensitive to
figure/ground
Good continuation
Elongated contours are
created by communication
among adjacent receptive
fields
Prägnanz
prefer the simplest or most
coherent interpretation
Principle of proximity
close objects are grouped
Principle of similarity
similar objects are grouped
Principle of common fate
objects moving together are grouped
Generalized cylinder
axis (= space curve)
• radius (= variable function)
Cylinder
axis (= straight line)
• radius (= constant)
Canonic view
preferred view, when an object can be identified most easily
Viewer-centered coordinate system
The tail is to the right of the wings)
→ implies viewpoint dependence
Object-centered coordinate system
(The tail is at the rear of the body)
→ implies viewpoint independence
Geons
(=“geometric ions”)
Individual part types that are combined in various
ways to form unique 3D object models
Object recognition is
viewpoint-dependent
Dichotic listening
Each ear gets a separate channel
Subjects typically can follow one but not the
other
Cocktail party effect
Highly salient stimuli can get through the nonattended
channel
Cueing experiments
Subject never moves their eyes
Cue is valid on 80% of trials, invalid on 20%
Dot detection is faster in cued location.
Attention is
like a spotlight that moves
about the visual field, enhancing perception
popout
• Some visual features seem to be detected (no attention required)
everywhere in parallel
Perception without attention
Some visual features seem to be detected
everywhere in parallel
Objects with the target feature “pop out”
without apparent search
Visual search paradigm
Response Time (RT) to detect the target as a function of the number of distractors
Conjunction search
a visual search process that focuses on identifying a previously requested target surrounded by distractors possessing one or more common visual features with the target itself.
Feature search: Target has feature X Distractors don’t No effect of #distractors → Parallel search
Parallel search
Searches all areas at once Feature search: Target has feature X Distractors don’t No effect of distractors due to popout
Serial search
Searches one area at a time, requires attention
Target: feature conjunction (shares a feature with distractors)
Linear effect of #distractors (the more distractors, the less likely you are to find the object)
What combines in the attentional window?
feature maps (orientation, color, size, motion, etc.)
The success of Samuels’ checker program suggests that
computer programs can exceed the abilities of their programmer
If an OR gate gets two inputs and one is ON and one is OFF, what is the output?
ON
One of Turing’s examples of an “argument from a disability” is that
a computer can’t enjoy strawberries and cream
If an AND gate gets two inputs and both are ON, what is the output?
ON
Consider the logical expression “1+1=2” OR “1+1=3”. Using the Boolean definition of OR we discussed in class, is this expression TRUE?
Yes
If a neuron has two excitatory inputs, and has a threshold of 1
it acts like an OR gate
One of my cats is always nervous. According to Locke, this is probably due to
her experience as a kitten
What does a split-brain patients left hemisphere see?
the right visual hemifield
Behaviorism assumes that learning proceeds by learned associations
between stimulus and response
If you ask a split brain patient what she sees, she is most likely to name
what is in her right visual hemifield
A single, general mechanism that works the same way in all learning contexts is an idea associated with
behaviorism
The two hemispheres are connected by the
corpus callosum
To empiricists, the human mind begins as a
blank slate
Behaviorism descends from
Empiricism
‘Depth ambiguity’ refers to the fact that
the depth dimension is missing in the proximal stimulus
A grandmother cell is
a neuron that only knows about your grandmother
Photoreceptors are found in
the retina
Which are more sensitive to light?
Rods
The Ames room illustrates a
failure of size constancy
Where is the density of photoreceptors the highest?
The fovea
A brain scan indicating the localization of a particular cognitive function probably shows
brain activity in an experimental task
A mental representation that matches the distal stimulus is
veridical (true)
“Inverse optics” corresponds to the
formation of the distal image of the retina
Which side completes behind the nearer object?
Ground
Dark red and light blue differ in both
hue and saturation
Edge detector cells are found in
primary visual cortex
If you stare at a blue path for a minute and then look at a white field, what color will the afterimage be?
Yellow
An off-center-surround cell responds most to
dark spot on a light background
An on-center-surround cell responds most to
a bright spot on a dark background
What principle says to prefer the most coherent interpretation of the proximal stimulus?
Pragnanz
The principle of common fate says to
group items with common motion together
