A set of statements (called hypotheses) about underlying mechanisms or principles organizes that explains known facts and predicts new ones
The best theory is the one most parsimonious (accounts for the empirical evidence with the fewest assumptions).
Asked "Why do things look as they do?"
3 "classical" issues that form the core of psychological theories of visual perception
1. Environment versus organism
2. Empiricism versus nativism
3. Atomism versus holism
Environment versus organism
"Because the world is the way it is" - emphasizes analyzing external stimulus to understand perception
"Because we/our visual nervous system are the way they are" - emphasizing an internal approach to perception (nature of organism).
Empiricism versus nativism
"Because we have learned to see them that way" - experience
"Because we were born to see them that way" - evolution has supplied the necessary neural mechanisms (we are programmed/ maturation)
Atomism versus holism
"Because of the way in which each small piece of the visual field appears" - by putting together the bits of visual experience in each local region
"Because of the way the whole visual field is organized" - they one part of the visual field appears perceptually will be affected by the other parts.
Introspection versus behaviour
"Why do things look as they do" - conscious experience
"What does vision enable us to do"
4 Psychological theories of perception
Structuralism (Wilhelm Wundt / British empiricism)
When basic sensory atoms evoke memories of other sensory atoms that have been associated in memory through repeated joint occurrences.
Claimed that one could discover the elementary units of their perception by turning one's mind inwards (______) and observing one's experiences.
Gestalt (Max Wertheimer)
"The whole is different from the sum of its parts"
in gestalt where new properties emerge when you put small parts together (a line emerging from some dots)
One's perceptual experiences are the same as underlying brain events (opponent process theory's afterimage of colours of the 3 psychological pairs of colours)
Physical gestalt (Wolfgang Kohler)
A dynamic physical system that converges toward an equilibrium state of minimum energy (bubble that gets bigger until it pops)(also said electrical brain fields had all the important properties of a ______)
Ecological optics (James J. Gibson)
about informational basis of perception in the environment rather than its mechanistic basis in the brain.
"Ask not what's inside your head but whats your head inside of"
The structure of an organisms environment
when a surface of uniform texture (distal stimulus) is slanted in depth, its image on the retina (proximal stimulus) forms a ________
Sufficient information is available in retinal stimulation to allow an actively exploring organism to perceive the environment unambiguously.
where the brain is like tuning forks, in that whatever the brain was doing in detail was analogous to a process of mechanical resonance. (information in stimulus causes neural structures to fire)
the array of information in our sensory receptors, including the sensory context, is all we need to perceive anything
Unconscious inference (Hermann von Helmholtz)
used to transfer insufficient 2-D optical information into a perceptual interpretation of the 3-D environment by using hidden "assumptions".
A probabilistic view of perception in which the visual system computes the highest probability given the retinal stimulation. (circle occluded by a square)
Principle of Pragnaz (minimum principle by Gestaltists)
the basis for selecting among possible interpretations is the "goodness" or "simplicity" of alternatives
Heuristic interpretation process
in which the visual system makes inferences about the most likely environmental condition that could have produced the image. (earthquake room) (if its false it leads to illusions)
3 important developments that changed the evolution of vision science as an interdisciplinary field
1. Computer simulations
2. Application of information processing ideas to psychology
3. The brain is a biological processor of information
Turing machine (Alan Turing)
machines that could be programmed to process information automatically in a theoretically infinite variety of ways. (all machines now are examples of this)
Artificial intelligence (AI)
The branch of computer science in which computer programs are written to simulate intelligent behaviour.
the study of how computers can be programmed to extract useful information about the environment from optical images.
2 important developments of computer vision
1. Real images - computer vision changed by allowing theories to be tested on real images instead of theoretical unrealistic ones.
2. Explicit theories - forces the theorist to make everything explicit in stead of vague and general.
A "microworld" in which all of the to-be-perceived objects were simple, uniformly colored, geometrical solids on a flat table top, like a child's set of blocks.
changes in the amount of light falling in two adjacent regions of the image.
Connectionist network (neural network)
models based on the assumption that human vision depends heavily on the massively parallel structure of neural circuits in the brain.
Corresponds roughly to the firing rate of a neuron
much like synapses that are either excitatory or inhibitory through neurons communication.
A particular class of neuron-like network models that were studied. (they were able to learn how to identify examples of new categories by adjusting the weights on their connections according to explicit rules)
Parallel distributed processing (PDP) models
Believed that the proper approach to psychology was to deal only with directly observable behavior.
a momentary sensory memory of visual stimuli; lasting no more than a few tenths of a second
retinal ganglion cells
influences the firing rate of target neurons by excitation or inhibition. (to make them respond vigorously it was a on centre pattern or reverse)