Review Sheet Perceprion
What is the relationship between sensation and perception?
Percept is what we perceive / a product of peception
Perceptual Processing
Feature Detectors - specialized cells dedicated to the detection of specific stimulus features
Binding Problem - how does our brain combine all these sensory operations into a single percept?
1. Top-Down Processing – conceptually driven processing - use the past and present and we perceive by filling in gaps in what we sense
Schemata
Perceptual set
Perceptual Constancies: color, shape, and size
2. Bottom-up Processing, also called stimulus - driven or feature analysis – we use only the features of the object itself to build a complete perception
Perceptual Ambiguity and Distortion:
What do illusions teach us about perception?
Herman Grid
Tops Down Processing
Mueller Lyer Figure
Necker Cube
Phi Phenomenon click on PICTURE - apparent movement based on sequential presentation of stationary images - fireworks vreate that pattern as well
Classical Explanations for Perception
GESTALT RULES- How we organize stimulation into meaningful patterns based on the way our brain is structured (innate)
Proximity
Similarity
Continuity
Closure
Figure Ground
CONSTANCY- Tendency to perceive objects as stable and unchanging despite changes in sensory stimulation
- Size constancy - Perception of an object as the same size regardless of the distance from which it is viewed
- Shape constancy - Tendency to see an object as the same shape no matter what angle it is viewed from
- Brightness constancy - Perception of brightness as the same, even though the amount of light reaching the retina changes
LEARNING BASED PERCEPTION
HELMHOLTZ - We use prior learning to interpret new sensory information / inferences based on what we know
Context
Expectations
Perceptual Set
Cultural Influences
DEPTH CUES
Visual cliff experiment-Gibson and Walk Experiment
Monocular cues - Visual cues requiring the use of one eye
Interposition - Monocular distance cue in which one object, by partly blocking a second object, is perceived as being closer.
Linear perspective - Monocular cue to distance and depth based on the fact that two parallel lines seem to come together at the horizon
Relative size-Monocular cue in which closer objects seem larger than distant objects
Texture gradient-Course objects appear closer than smooth objects
Shadowing-lighter objects appear closer than darker objects
Binocular cues - Visual cues requiring the use of both eyes
Retinal disparity - Binocular distance cue based on the difference between the images
Convergence- cast on the two retinas when both eyes are focused on the same object
Stereoscopic vision - Combination of two retinal images to give a three-dimensional perceptual experience.