chapter 2

Question 1

visual perception two phases

Answer 1

-an early phase in which shapes and objects are extracted from the visual scene
-a later phase in which the shapes and objects are recognized.

Question 2

explain the cortical structures involved in visual and audition

Answer 2

early visual processing goes on in the occipital cortex, later processing takes one of two paths
-might have activity going into the temporal lobe, the “what” visual pathway, trying to identify what you are seeing (ventral)
-might have activity going into the “where” visual pathway, understanding the spatial relationship between things, focusing more on where things are (dorsal)

Question 3

explain visual agnosia

Answer 3

Inability to recognize visual objects, which is neither a function of general intellectual loss nor a loss of basic sensory abilities

Two types:
-Apperceptive
-Associative

Question 4

what is apperceptive agnosia

Answer 4

-Inability to recognize simple shapes or draw shapes that are shown
-Early processing problems
-As soon as information gets into the occipital lobe, you have trouble dealing with it

Question 5

what is associative agnosia

Answer 5

-Ability to recognize simple shapes and copy drawings of complex objects, but not to recognize complex objects
-Later processing problems
-Ex. Able to copy a picture of an anchor, but unable to say what it is

Question 6

early visual processing overview

Answer 6

Early visual information processing begins in the eye.

Light passes through the lens and the vitreous humor and falls on the retina at the back of the eye.

The retina contains the photoreceptor cells, which are made up of light-sensitive molecules that undergo structural changes when exposed to light.

Light is scattered slightly when passing through the vitreous humor, so the image that falls on the back of the retina is not perfectly sharp.
-The right and left nerves coming from the eyes cross over within the brain, right and left genicular regions receive information from opposite eye
-Eg. Left visual field goes to the right occipital lobe

One of the functions of early visual processing is to sharpen that image.

Question 7

what is the fovea

Answer 7

You have the most visual acuity when you hold things in front of your fovia, the center of your eyes

-A small area in the center of the retina, composed primarily of cones
-Where visual information is most sharply focused

Question 8

what are rods

Answer 8

-Long, thin, blunt sensory receptors of the eye that are highly sensitive to light, but not to color
-Primarily used for peripheral and night vision

Question 9

what are cones

Answer 9

-Short, thick, pointed sensory receptors of the eye that detect color
-Responsible for color vision and visual acuity

Question 10

what is the optic disk

Answer 10

-Area of the retina without rods or cones
-Where the optic nerve exits the back of the eye

Question 11

what is the optic nerve

Answer 11

-The thick nerve that exits from the back of the eye
-Carries visual information to the visual cortex and brain

Question 12

what are the ganglion cells

Answer 12

-In the retina, the specialized neurons that connect to the bipolar cells
-Bundled axons of the ganglion cells form the optic nerve.

Question 13

what is the blind spot

Answer 13

The point at which the optic nerve leaves the eye, producing a small gap in the field of vision

Question 14

explain neural pathways from the eye to the brain

Answer 14

Neural Pathways from the Eye to the Brain
-Optic nerves meet at the optic chiasma

Question 15

explain depth cues

Answer 15

-Information from the retina is 2-D, but 3-D representation is needed.

The visual system uses cues to infer distance:
-Texture gradient
-Stereopsis
-Motion parallax

Question 16

explain texture gradiant

Answer 16

Elements tend to appear more closely packed together as the distance from the view increases.

Question 17

what is stereopsis

Answer 17

The ability to perceive 3-D because two eyes receive slightly different view of the world

Question 18

what is motion parallax

Answer 18

-Provides information about a 3-D scene when you are in motion
-More distant points move more slowly across the retina than closer points

Question 19

what are the gestalt principles of organization, how they explain the brain segments visual scenes into objects

Answer 19

Principle of proximity
-Lines picture, brain organizes them into four bars rather than 8 lines, the lines are closer together and our brain thinks that things that are closer together go together

Principle of similarity
-Lines of circles and x’s rather than alternating shapes that make up columns, we group similar objects together

Principle of good continuation
-Two lines crossing each other, one from A to B and one from D to C, we try to maintain continuity

Principle of closure
-Two circles overlapping each other rather than seeing a jagged line, we see whole objects

Question 20

what is object perception

Answer 20

-Gestalt principles tend to organize even novel stimuli into units.

Palmer (1977) found that participants could recognize the parts most rapidly when they were the segments predicted by the gestalt principles.
-Psychological reality/purpose of why we follow the gestalt principles

Question 21

explain template matching theory (how we recognize things)

Answer 21

Image of an object is faithfully transmitted to the brain

an attempt is made to compare it directly with various stored patterns
-These patterns are called templates

An attempt is made to achieve correspondence between the retinal cells stimulated and the retinal cells specified for a template pattern.

Used in machine pattern recognition

Question 22

what is feature analysis

Answer 22

Stimuli are thought of as combinations of elemental features.

What we store in our long-term memory are its parts/features.

Compare retinal image to objects in long-term memory

Look for corresponding features

Advantages over template model
-Features are simpler, and it is easier to extract the separate features.
-Can specify those relationships among the features that are most critical to the pattern.
-The use of features rather than large patterns will reduce the number of templates needed.

Question 23

explain disintegration of an image that is stabilized on the eye

Answer 23

Display the combined image so that is completely still in front of the eye, overtime pieces of the letter or image you are staring at will disappear; so they set up things so that the eye could not get fatigued
-You are always moving a little bit and your eye has a slight tremor, over time it will be fatigued and not work
-People would report the letters or shapes they saw, H, B, 3, 4, kept track of which features of the original image disappeared

Question 24

explain recognition by components theory

Answer 24

Biederman proposes three substages:

1) The object is segmented into a set of basic subobjects using early visual processing.

2) Once an object has been segmented into basic subobjects, one can classify the category of each subobject.
-36 basic categories of subobjects, called geons

3) Having identified the pieces out of which the object is composed and their configuration, one recognizes the object as the pattern composed from these pieces.

Question 25

what are deep convolutional networks

Answer 25

Neural networks that can be used to recognize things

Question 26

explain visual pattern recognition (what do humans tend to recognize)

Answer 26

humans tend to recognize faces

Question 27

what is prosopagnosia

Answer 27

Selective difficulties in recognizing faces due to damage to the temporal lobe

Question 28

what is the fusiform gyrus

Answer 28

The region of the temporal lobe that responds when faces are present in the visual field
-May be stronger in right hemisphere (McCarthy et al., 1997)

Question 29

what is the alternative explanation for the fusiform gyrus

Answer 29

But fusiform gyrus could just activate when accessing your expertise
-People are “face experts”
-It’s activated when hobbyists make judgments about their hobbies
-It’s activated when greeble experts make judgments about greebles

Question 30

what is bottom up processing

Answer 30

Information from the physical stimulus is used to help recognize a stimulus.
-Start with small bits of information and combine them to form your perception.

Question 31

what is top down processing

Answer 31

Information from the general context is used to help recognize a stimulus.
-High-level general knowledge contributes to the interpretation of the low-level perceptual units.

Question 32

what is the word superiority effect

Answer 32

Superior recognition of letters in a word context rather than alone
-Word context can be used to supplement information in the recognition of letters.
-Supports a top-down approach.
-Can identify a letter in between a word in shorter amounts of time than identifying a singular letter on its own

Question 33

what is Massaro’s FLMP model for combination of context and feature information

Answer 33

FLMP (Fuzzy Logical Model of Perception)
-Claims that stimulus features and context combine independently to determine perception
-Asked people to respond if they are seeing a C or an E, with different levels of clarity and different letters in each word, some words are only words with c, some are only words with e, and some are words with either, some are words with neither
-The main effect of context, context always mattered, when context suggested it was an e people were more likely to say it was an e
-Main effect of stimulus, the more it looked like an e the more likely people were to say it was an e

Question 34

what is the phoneme sound restoration effect and the study that goes along with it

Answer 34

Our perceptual systems will add back in phonemes that were deleted from an utterance.
-When we don’t hear a part of a word we will later on remember that we did hear it

Warren and Warren (1970)
-It was found that the *eel was on the axle.
-It was found that the *eel was on the shoe.
-It was found that the *eel was on the orange.
-It was found that the eel was on the table.
-identification of word is determined by what comes after, not instantaneous
-When asked what they heard people would fill in the sounds

Question 35

what is the Biederman et al study about using context information

Answer 35

Context information can be used to supplement feature information in the recognition of faces and scenes.
-Ex. Cutting up a picture into 6 pieces and reorganizing them, you might see either picture (together or scrambled) and you had to determine what was in the spot in the picture for either image
-It was easier for people to do this with the scrambled one, because they did not have context, it was harder for them to decode

Question 36

what is change blindness

Answer 36

The phenomenon that people are unable to keep track of all the information in a typical complex scene
-Ex. They have a person talking to someone else and then switch someone in mid conversation
-You decode important information (giving directions) you might not notice the color of their shirt