Perception basics and patter recognition Flashcards
Sensation
the process of the sensory organs transforming physical energy into neurological impulses
Perception
selection, organization, and interpretation of sensory input
PsychoPhysics
the study of how physical stimuli are translated into psychological experience.
Basic Principles when it comes to sensation and perception:
- there is not a one-one correspondence between physical and psychological reality
- are active processes (activley taking in information)
- are adaptive (help us survive)
Perception processes
response → representation→proximal stimulus→ distal stimulus
Distal stimulus
whats actually out there
Proximal stimulus
- sensory info impinging on sensory receptors
- have info about the proximal stimulus but not the distal stimulus
Illusory Contours
perceptual system fills in the gaps that are not present in the image (the triangle and square illusions)
Perception as induction:
- perception makes inferences to simplify interpretation of sensory info
- with partial or missing sensory information, perception must fill in the gaps to infer what is out there in the world
top-down processing
It refers to how our brain utilizes existing knowledge and expectations to interpret new sensory information.
bottom-up processing
sensory data and goes up to the brain’s integration of this sensory information
-perception changes based on what you expect to see
Gesalt Principles: Proximity
things that are next to each other are automatically grouped together
Gesalt Principles: similarity
things that are similer probably go together
Gesalt Principles: good continuation
if lines intersect we see the line is continuing on
Gesalt Principles: closure
if one object is covering another object we see it as overlapping not missing
Pattern recognition:
- translated patterns of sensory information into psychological experiences of recognizable objects
- pattern recognition matches sensory info to represent in memory
Template Matching
simple notion is that objects are matched to a template stored in memory
Feature Analytic Approach
- break stimuli into smaller components and then using those feature to recognize the objects
- recognition based on detection of distinktive features
- objects are defines by their unique set of features
Physiological Basis for Feature Theory
- microelectrode recording of axons in primary visual cortex of animals
- trying to see what the features of the neuron firing to
- showed the animal different stimuli to see their differences in neural firing
- moved the line on the projector and the nueron fired
feature detectors
neurons that respond selectivley to lines, edges etc.
Simple Cells
receptive field responds to linear stimuli at a particular orientation
Complex Cell
receptive fields responds optimally to a stimuli at a particular orientation and move in a particular direction
- when it moves up in the visual field the cell fires and when it goes down it doesn’t fire
Hypercomplex Cells:
recepetive fields optimally responsive to movement, orientation and length
Feature analytic Approach
- complex representations must be built up of simple representations present in early vision
- simple features early in the cortex get more complex the further up you go
complex feature detection in monkeys
neurons fire when the monkeys saw a monkey faces and as the monkey face turns the neuron fires less and doesnt fire at all when its unanimate objects
Feature Analysis in Audition
understanding of spoken languages is notable example of feature analysis in perception
