Chapter 3 - Visual Perception Flashcards
Light transfer
catching the light that is reflected by the world from the opening/constricting of the pupil and the tightness and bulging of the lenses
- light -> cornea -> lens -> retina
Photoreceptors
Specialized neural cells that respond directly to incoming light
Rods and Cones
Rods - low levels of light, low acuity, no colour sensitivity, peripheral view only
Cones - high levels of light, high acuity, high colour sensitive, mostly in fovea
Bipolar Cells
Receive input from photoreceptors and transmit them to ganglion cells
Ganglion Cells
- spread across retina and their axons converge to make the optic nerve which caries info to the LGN where it is transmitted in the V1
Visual System - V1
- photoreceptrs
- bipolar cells
- ganglion cells (most inwards)
- LGN of the thalamus
- area f V1 of the occipital lobe
Lateral inhibition
A way to analyze visual input as information is passing through the LGN to the V1
- When cells are stimulated they inhibit the activity of neighbouring cells
- enhances the contrast of the image
Edge Enhancement
Apart of lateral inhibition which exaggerates the contrast at the edge
Receptive Field
The size and shape of the area in the visual world to which that cell responds
Parallel Processing
Simultaneous processing of stimuli and multiple tasks going on at the same time
Advantage - speed, efficiency
What and Where System
- Apart of parallel processing
- What - temporal; where - parietal
Binding problem
Putting elements of a figure together when usually those elements are done separately in different areas of the brain
- the task of reuniting elements the various elements of a scene, elements that are initially addressed by different systems in the different areas of the brain
Solving binding problem
Spatial position - by integrating where in space the stimulus is and what is its overlapping regions, the brain can bind info together
Neural synchrony - since neurons are firing together, the brain links them together as the same stimulus
Attention - when there is not enough attention binding features could be compromised leading to conjunction errors could occur
Gesalt principles (whole is different than sum of its parts)
Similarity – group dots into columns rather than rows, grouping dots of similar color
Proximity – group linking dots that are close together
Good continuation – continuous green bar than 2 similar rectangles
Closure – an intact triangle reflecting bias toward perceiving closed figures rather than incomplete ones
Simplicity – interpret a form in the simplest way possible.
Perceptual Constancy
perceive the constant properties of objects in the world even thought the sensory information we get about these attributes change whenever our viewing circumstances change (shape, size, brightness)
