Introduction to Cognitive Science
Computational Theories of Consciousness
Vision (& Perception)
Last Update: Thursday, 31 July 2014
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"[T]he task of the brain, when viewed from a certain distance, can seem
impossible: it must discover information about the likely causes of
impinging signals without any form of direct access to their source.
…[A]ll that it ‘knows’, in any direct sense,…[is]
the ways its own states (e.g., spike trains) flow and alter. In that
(restricted) sense, all…[it] has direct access to is its own
states. The world itself is thus off-limits. …Notice how
different this conception is to ones in which the problem is posed as
one of establishing a mapping relation between environmental and inner
states. The task is not to find such a mapping but to infer the nature
of the signal source (the world) from just the varying input signal
itself. [§1.2, p. 183.]
"If ["perception is indirect" (J. Hohwy, "Functional Integration and
the Mind", Synthese 159(3) (2007): 315–328)]…, then
the role of perceptual contact with the world is only to check and, when
necessary, correct the brain's best guessing concerning what is out
there.
"Nevertheless, we may still reject the bald claim that ‘what we
perceive is the brain's best hypothesis.’ …[W]hat we
perceive is not some internal representation or hypothesis but
(precisely) the world." (§4.4, p. 200.)
-
Clark, Andy (2013),
"Whatever Next? Predictive Brains, Situated Agents, and the Future of
Cognitive Science",
Behavioral and Brain Sciences
36: 181–253.
-
See also:
Clark, Andy (2013),
"Expecting the World:
Perception, Prediction, and the Origins of Human Knowlede",
Journal of Philosophy 110(9) (September): 469–496.
"[T]he brain is a creativity machine, which obtains incomplete
information from the outside world and completes it."
"[T]hese findings [about "neural correlates for illusions involving
senses other than vision, such as hearing and touch"] demonstrate that
we have no direct contact with reality. Our brain is always
abstracting and interpreting the world around us."
- Hood, Bruce (2012), "Re-Creating the Real World:
To What Extent Do We Truly Experience Reality?", Scientific American
Mind 23(4) (September-October): 43 45; quote on p. 45.
"Open a standard textbook on neurobiology and you will find somewhere an
illustration with an eye on one side and the primary visual cortex on
the other. Signals flow from the eye's retina to the optic
chiasm; then on to the lateral geniculate, explained as a kind of way
station; and then to the primary visual cortex. It is a comfortable
diagram. We engineer such systems, with a few modules lined up from left
to right, with information flowing through them.
The trouble is, neurobiology textbooks also note that 80% of the input
to the lateral geniculate comes from somewhere other than the retina. A
good deal comes down from the primary visual cortex, suggesting that
vision is a matter of guided hallucination. Other substantial input
comes from auditory apparatus. Everything is all mixed up, with
information flowing bottom to top and top to bottom and sideways too. It
is a strange architecture about which we are nearly clueless."
"Light bouncing off stuff is what we see."
-
Church, Jok (2012, 4 November), "Why is the sky blue?",
UCan with Beakman & Jax (Buffalo News).
"The ‘magic’ of consciousness is that we think we are
experiencing the world through our eyes and ears, but really everything
is seen and heard in the brain."
-
Proulx, Michael J. (2011), "Consciousness: What, How, and Why",
Science 332 (27 May): 1034–1035; quote on p. 1034.
"Reality is a tape-delayed broadcast, carefully censored before it
reaches us."
-
Bilger, Burkhard (2011), "The Possibilian: What a Brush with Death
Taught David Eagleman about the Mysteries of Time and the Brain",
New Yorker (25 April): 54–60, 62–65; quote on
p. 60.
"Our perceptions…are fantasies we construct that correlate with
reality."
-
Brooks, David (2011), "Social Animal: How the New Sciences
of Human Nature Can Help Make Sense of a Life", New Yorker
(17 January): 26–32; quote on p. 31.
"Your brain, after all, is encased in darkness and silence in the vault
of the skull. Its only contact with the outside world is via the
electrical signals exiting and entering along the super-highways of
nerve bundles. Because different types of sensory information (hearing,
seeing, touch, and so on) are processed at different speeds by different
neural architectures, your brain faces an enormous challenge: what is
the best story that can be constructed about the outside world?"
"My phenomenal
world…[is] a neural fiction perpetrated by the senses."
- Edelman,
Shimon (2008), Computing the Mind: 426.
"It is a gross mischaracterization to say that we simply open our eyes
and take it all in; what we are in contact with is a constructed product
of many different brain processes."
- Kolak, Daniel;
Hirstein, William;
Mandik, Peter;
&
Waskan, Jonathan
(2006),
Cognitive Science: An Introduction to Mind and Brain
(New York: Routledge): 81.
"Biological systems have available through their senses only very
limited information about the external world. Yet these systems make
strong assertions about the actual state of the world outside
themselves. These assertions are of necessity incomplete. Clearly, a
[complete]
replica of an object and its qualities cannot be embodied within the
brain. How can an incomplete description, encoded within neural states,
be sufficient to direct the survival and successful adaptive behavior of
a living system?"
-
Richards, Whitman (1988), Natural Computation (Cambridge, MA:
MIT Press)
(from the introduction; as cited in Ballard, Dana (1997), An
Introduction to Natural Computation (Cambridge, MA: MIT
Press): 2).
For more on the limitations and distortions of vision, watch:
Vsauce (2013),
"What Does Earth Look Like?" (11 November).
-
The visual system in the brain:
- retina
-
Figure 06-03. The eye. (a) Illustration showing how objects in the
environment are physically projected to the back of the eye&151;the retina. (b) The eye and a cross-section of the retina. The
cross-section of the eye shows where the photoreceptors are located in
the retina. Both the rods and cones are shown. They respond to different
types of light. The neural signal then travels via bipolar cells and
then to the ganglion cells. The axons of the ganglion cells take the
neural information out of the eye and backward toward the cortex.
Source: Squire et al., 2003.
- from retina to cortex
-
Figure 06-07. The visual pathways from retina to cortex. (a) Example
of a brain slice from a functional magnetic resonance imaging (fMRI)
scan, showing the lateral geniculate nucleus (LGN) and primary visual
areas at the back of the brain (the occipital cortex). The two different
colors denote the two hemispheres of the brain. (b) Schematic
illustration showing the visual pathways from the retina in the eyes to
the primary visual cortex at the back of the brain. You can see here
that the neural information from the nasal or inner sides of the eyes
crosses over at the optic chiasm, to be processed in the contralateral
side of the brain. The left visual field, in blue, is processed by the
right visual cortex (also blue). The LGN, displayed in green, relays the
visual information to the primary visual areas of the cortex. Source:
Squire et al., 2003.
- hierarchy of visual
processing
-
Figure 06-10. The hierarchy of visual processing. A demonstration of
the hierarchical response properties of the visual system to simple and
complex stimuli. The leftmost column shows our house stimulus and what
receptive fields of each visual area we would see in the balloons. Not
only do the receptive field sizes increase in each visual area, but also
the complexity of the shapes they respond to. The rightmost column shows
an estimate of where each area is in the brain. You can see that early
visual areas respond to simple features and, as we move along the
processing stream, areas respond to more complex shapes and objects.
This is a well-established theme of the visual system.
-
From
"Neuroscience and Behavior Links"
at UB's
"Neuroscience and Behavior Explore—Learn—Enjoy" page:
"This site at the University of Western Ontario has many
tutorials
that
explain physiological concepts of each of the sensory and motor
systems."
-
Lamb, Trevor D.
(2011),
"Evolution of the Eye",
Scientific American 305(1) (July): 64–69.
-
How Saturn with its rings looked to early astronomers
-
Gibson, James J.
(1979),
The Ecological Approach to Visual Perception
(Boston: Houghton Mifflin).
-
Fodor, Jerry A.;
&
Pylyshyn, Zenon
(1981),
"How Direct is Visual Perception?
Some Reflections on Gibson's 'Ecological Approach' ",
Cognition 9: 139-196.
-
Marr, David
(1982),
Vision:
A Computational Investigation into the Human Representation and Processing
of Visual Information
(New York: W.H. Freeman).
- An excerpt, under the title
"Vision",
is reprinted in
Cummins, Robert; & Cummins, Denise Dellarosa (eds.) (2000),
Minds, Brains, and Computers:
The Foundations of Cognitive Science, an Anthology (Malden, MA:
Blackwell): 69-83.
-
what we see depends on what we believe?
- primal sketch
- 2½D sketch
- From Green, David W. (ed.),
Cognitive Science: An Introduction
(Oxford: Blackwell): 94 (Fig. 4.4).
-
3D sketch
-
Biederman, Irving
(1987),
"Recognition-by-Components:
A Theory of Human Image Understanding",
Psychological Review 94: 115-147.
-
Gregory, Richard L.
(1997),
Eye and Brain:
The Psychology of Seeing, 5th Edition
(Princeton, NJ: Princeton University Press).
-
Hayes, Brian
(1999),
"Seeing between the Pixels",
American Scientist
87(May-June): 202–207
-
Simons, Daniel J. (2005),
Visual Cognition Lab
- movies
-
See also:
Bloom, Paul
(2010),
"What We Miss…",
New York Times Book Review
(6 June): 30.
- "We tend to believe what we see, and what we
remember, even if it never happened."
- This is a review of:
Chabris, Christopher; & Simons, Daniel
(2010),
The Invisible Gorilla; and Other Ways Our Intuitions
Deceive Us
(Crown).
-
Changizi, Mark A.;
Hsieh, Andrew;
Nijhawan, Romi;
Kanai, Ryota;
& Shimojo, Shinsuke
(2008),
"Perceiving the Present and a Systematization of Illusions",
Cognitive Science
32(3) (April-May): 459–503.
-
Cyclopean vision example
- Vision in Non-Human Animals:
-
On Hearing & Sound:
-
One of the earliest, if not the
original, sources of "If a tree falls and no one hears it,
does it make a sound?" (with a local, Western New York connection):
- "Sounds are made in…mechanical pressure waves,
which is a fancy way of saying sound is a bunch of pushes through
something like air. When those pushes get to your ears, your brain
turns them into things you hear." —Church, Jok (2012), "Beakman
Jax" (comic strip), Buffalo News (29 July).
-
Hoy, Ronald R. (2012),
"Convergent Evolution of Hearing",
Science 338 (16 November): 894–895.
- Discusses how human (and insect) ears work.
-
On Pain:
-
Can Plants (and other non-higher-animal biological organisms) Sense?
(Click on the link above to find out!)
Text copyright © 2007–2014 by William J. Rapaport
(rapaport@buffalo.edu)
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