Chapter 3: Perception

Question 1

Perception

Answer 1

the act of becoming aware of something through stimulation of the senses; pattern recognition

Question 2

Pattern recognition

Answer 2

ability to detect meaningful patterns in the environment

Question 3

Inverse projection problem

Answer 3

task of determining the object responsible for creating a particular image on the retina; starts with the retinal image then extending rays out from the eye

Question 4

Viewpoint invariance

Answer 4

people’s ability to recognize an object even when it’s seen from different viewpoints or angles

Question 5

2 types of information used by the human perceptual system

Answer 5

(1) environmental energy stimulating the receptors (2) knowledge and expectations that the observer brings to the situation

Question 6

Size constancy

Answer 6

an object is the same size at different distances; it is just smaller on the retina when farther away

Question 7

Bottom-up processing

Answer 7

basic elements come together until the mind reaches a higher level of understanding (e.g. an image generates electrical signals transmitted to the retina then to the brain’s visual receiving area)

Question 8

Top-down processing

Answer 8

originates in the brain; prior knowledge or context are used to analyze incoming information to inform perception (e.g. perceiving objects in different scenes)

Question 9

Speech segmentation

Answer 9

the ability to tell when one word in a conversation ends and when the next one begins

Question 10

Transitional probabilities

Answer 10

likelihood that one sound will follow another within a word

Question 11

Statistical learning (Saffran)

Answer 11

the process of learning about transitional probabilities and other characteristics of language; as early as 8 months old through passive learning

Question 12

Helmholtz’ theory of unconscious inference

Answer 12

some of our perceptions are the result of unconscious assumptions we make about the environment

Question 13

Likelihood principle

Answer 13

we perceive the world in the way that is most likely to have caused the pattern of stimuli we have received, based on our past experiences

Question 14

6 Gestalt principles of perceptual organization

Answer 14

similarity, proximity, closure, common fate, symmetry, good continuation

Question 15

Similarity principle

Answer 15

elements that look similar will be perceived as part of the same form or group

Question 16

Proximity principle

Answer 16

elements that are close together will be perceived as a coherent group

Question 17

Closure principle

Answer 17

humans tend to enclose spaces by completing an illusory contour and ignoring gaps in a picture

Question 18

Common fate principle

Answer 18

If two or more objects are moving in the same direction and at the same speed, they tend to be perceived as a group

Question 19

Symmetry principle

Answer 19

images that are perceived as symmetrical are perceived as belonging together

Question 20

Good continuation principle

Answer 20

people tend to connect elements in a way that makes the elements seem continuous or flowing in a particular direction; objects that are overlapped by other objects are seen as continuing behind those objects

Question 21

Bayesian inference

Answer 21

top-down process; our estimate of the probability of an outcome depends on its prior probability and the likelihood

Question 22

Apparent movement (Wertheimer)

Answer 22

movement is perceived even though nothing is actually moving (e.g. rapidly alternating pictures)

Question 23

3 components to stimuli that create apparent movement

Answer 23

(1) one light flashing on and off, (2) a period of darkness lasting a fraction of a second, (3) second light flashing on and off

Question 24

2 conclusions from apparent movement

Answer 24

(1) it cannot be explained by sensations because there’s nothing in the dark space between flashing lights, (2) the whole is different than the sum of its parts, one of the basic principles of Gestalt psychology

Question 25

Law of pragnanz/Principle of good figure or simplicity

Answer 25

every stimulus pattern is seen in such a way that the resulting structure is as simple as possible

Question 26

Regularities in the environment

Answer 26

frequently occurring characteristics of the environment, either physical or semantic

Question 27

Physical characteristics

Answer 27

regularly occurring physical properties of the environment (e.g. vertical and horizontal orientations)

Question 28

Oblique (angled) effect

Answer 28

we perceive verticals and horizontals more easily than other orientations; can be explained by theory of natural selection

Question 29

Light-from-above assumption

Answer 29

we assume that light comes from above because light in our environment usually comes from above; we perceive shadows as specific information about depth and distance

Question 30

Semantic regularities

Answer 30

characteristics associated with the functions carried out in different types of scenes

Question 31

Scene schema

Answer 31

knowledge of what a given scene typically contains that help us perceive them faster

Question 32

Prior probability

Answer 32

our initial belief about the probability of an outcome

Question 33

Likelihood

Answer 33

the extent to which the available evidence is consistent with the outcome

Question 34

Brain ablation or lesioning

Answer 34

the study of the effect of removing parts of the brain in animals

Question 35

Ventral stream

Answer 35

i.e. what or perception pathway; from the visual cortex to the temporal lobe

Question 36

Dorsal stream

Answer 36

i.e. how or action pathway; from the visual cortex to the parietal lobe

Question 37

Mirror neurons

Answer 37

neurons that respond both when a monkey observes someone else grasping an object and when the monkey itself grasps the same object; distributed throughout the brain in a network called mirror neuron system; involved with understanding intentions behind actions

Question 38

Size-weight illusion

Answer 38

when a person is shown two similar objects (e.g. two cubes of same weight but different sizes), the bigger one is lighter than predicted

Question 39

Inferotemporal cortex

Answer 39

in the front end of the ventral stream; has cells selective for object categories and some regions are selective for faces; view invariant

Question 40

4 theories for bottom-up processing

Answer 40

distinctive features, recognition by components, template-matching, prototype

Question 41

Distinctive features theory

Answer 41

all complex perceptual stimuli are composed of distinct features; pattern recognition is done by mentally assessing the presence or absence of a checklist of features

Question 42

Recognition by components theory

Answer 42

pattern recognition done by identifying the building blocks that make up 3D objects; basic elements are composed of an alphabet of 36 primitive shapes called geons or geometric icons, which are compared to geon patterns stored in LTM and can be rotated in 3 dimensions

Question 43

Template matching theory

Answer 43

we store an unlimited number of patterns corresponding to every object that we have experienced; a new instance is matched to the stored template

Question 44

Limitations of template matching theory

Answer 44

impractical when the set of possible patterns is very large and inefficient because it fails to account for our ability to recognize new objects (w/o a stored template)

Question 45

Prototype theory

Answer 45

we store the average or typical instance of the many different views of an object called a prototype (not a literal match)

Question 46

Typical face processing

Answer 46

in a gestalt-like manner, using spatial relations among face parts to construct a holistic view

Question 47

How do we process faces when they’re upside down?

Answer 47

we switch to noticing individual facial features or the component information instead of the holistic view; more common for non-faces

Question 48

Feedforward process

Answer 48

mostly involved in bottom-up processing as information gets passe forward from one area to the next: V1 (primary visual cortex) to inferotemporal cortex

Question 49

Primary visual cortex

Answer 49

where information from the eyes reach the cortex (in the occipital lobe) and the beginning of both the dorsal and ventral streams

Question 50

Feedback process

Answer 50

mostly involved in top-down processing of face and object recognition as information gets passed backward from a higher level area to a lower level one: prefrontal cortex to V1

Question 51

Importance of frontal lobe in face and object recognition

Answer 51

predicts its identity and helps finetune the representation in the inferotemporal cortex

Question 52

Optic ataxia

Answer 52

a problem with visually-guided behavior stemming from impaired representations in the dorsal stream

Question 53

Apperceptive agnosia

Answer 53

failure of perception in which some basic visual functions are preserved (e.g. acuity, color, motion) while others are disrupted; damage to the ventral stream

Question 54

Associative agnosia

Answer 54

inability to recognize objects despite intact perception of basic visual characteristics, usually due to damage in the ventral stream

Question 55

Gist perception

Answer 55

the abstract meaning of a scene is automatically extracted (~150 ms) based on little information; happens unconsciously

Question 56

Scene layout perception

Answer 56

we can perceive the spatial layout of objects in a scene after a few seconds; repeated layouts are learned implicitly

Question 57

Statistical estimation/Ensemble perception

Answer 57

the perceptual system can quickly extract ensemble properties in less than 50 ms when there are many objects e.g. mean size, orientation, velocity, direction

Question 58

Pattern detection

Answer 58

perceptual system can detect trends or outliers in a graph; related to ensemble perception and gestalt grouping by proximity