Psy 342: Review for Exam 2

broadbeansromanceAI and Robotics

Nov 18, 2013 (3 years and 4 months ago)

77 views

Psy 342: Review for Exam 2

Chap. 4


The Visual Cortex and Beyond

Visual pathway: Retina
-
Optic Nerve
-
LGN
-
Optic Radiations
-
V1 (striate cortex)
-
other areas

Hubel and Wiesel (Nobel Prize) individual cell recording from V1

Simple cells (straight lines),
complex cells (motion), hypercomplex cells (edge detectors)

Mishkin: What (ventral to temporal lobe) and Where (dorsal to parietal lobe) pathways

Damage to What pathway causes agnos
ia (lack of object recognition) : prosopagnosia (face recognition)

Damage t
o Where pathway on right hemisphere may lead to contralateral neglect (lack of attention to left side)

Chap. 5

Perceiving Objects and Scenes

Problems in designing a perceiving machine

Viewpoint invariance: same object when viewed from different angles

Wund
t
-
Structuralism (perceive world by adding up the elements of sensation)

Wertheimer
-
Gestalt (whole is greater than the sum of its parts) Ex. Apparent motion

Gestalt laws: Pragnanz (good figure), similarity, continuation, proximity, common region, common fat
e (etc)

Figure ground principles
: more “thinglike”, figure in front, contour belongs to figure, lower part seen as figure.

Chap. 6

Visual Attention

Why is selective attention necessary?

Eye movements: saccades (small eyes movements). Three fixations a seco
nd

Attention govern
ed

by stimulus salience, knowledge about scene, nature of task, past learning.

Reddy experiments with central, peripheral and joint tasks. Do well on one task. Joint task: faces better than colored disks

Inattention blindness (Simons and

Chabris): 46% failed to see gorilla in film
.

Change blindness: fail to see changes in scenes. Continuity errors in films. Objects change without movement.

Attention people with autism tend to focus on things rather than people’s faces or actions. Problem
in r
eading intentions.

Chap. 9 Perceiving Color

Red, yellow, green and blue are primary colors. Part of visual spectrum.

Brown and purples are extraspectral.

Change color by altering intensity (brighter or dimmer) or saturation (by adding white)

Colors are

based on wavelengths that are absorbed, reflected or transmitted (thru tinted glass and liquids)

Additive (projected lights) and subtractive (mixing paints) color mixing.

Young
-
Helmholtz theory of color vision. Trichromatic theory. Three cones with different wavelength
pre
ferences

Color deficiency. Monochromats (no cones), Dichromats (two cones).

Protanopia and Deuteranopia (sex
-
linked, mostly males, red
-
green deficiency).

Tritanopia (not sex
-
linked, rare)

Herring’s
Opponent
-
Process theory of color vision. Red+green. Blue+yellow. Black+white. Evidence in afterimages.

Both theories work together. Trichromatic at retina. Opponent process in brain.