chapter three: perception

Question 1

chapter 3: perception

Answer 1

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Question 2

template-matching theory

Answer 2

A template of a visual stimulus is stored in memory.

• Presentation of visual stimulus is compared with
  templates stored in memory
• Templates linked to information about that type of object
  (e.g., its name, what it’s used
  for, what it does etc.).

notes:

An early theory of recognition is that of template matching. As the name suggests a template of every object in our environment is thought to be stored in memory when presented with a visual stimulus this stimulus is matched against templates

for example according to template matching theory the presentation of the letter a is matched templates and memory when there is a match the item is recognized

but you might wonder not every apple looks exactly the same not every letter 8 looks the same so how can a template match all these different versions of the same object? do we have a template for each variation within a category?

Question 3

problems with template matching theory

Answer 3

Problems:

• The way we see objects is highly variable.
• Requires a huge number of templates even for a single type of
  object.

the problem with template matching theory is that it does not explain why we can recognize objects that do not match a template in memory exactly for example we can recognize variations within a category, objects that are out of focus or visually degraded does this mean that we have a template for all the different types of hats? a template perhaps out of focus or when it is visually degraded?

if recognition requires that a template for each variation within a category be stored in memory this would mean we have an infinite number of templates learned and stored in memory this seems unlikely

Question 4

feature detection theory

Answer 4

Objects can be decomposed into parts (features)

The features are matched to the features of objects in
memory.

When there is large feature overlap between the stimulus and
item in memory this will lead to recognition.

notes:

Feature detection accounts for w recognition even when there is variation in objects by examining features of the object instead of the object as a whole like with template theory

feature detection theory proposes that objects such as the letter a can be decomposed into parts for example the letter a has 2 diagonal lines and a horizontal line when the features of an object match the features of a pattern in memory this will result in recognition

Question 5

FEATURE DETECTION THEORY

Neisser’s study

Answer 5

Neisser’s (1964) study

• If recognition involves feature detection there should be perceptual
  confusions. That is, impaired recognition of objects that share
  overlapping features (e.g., angular features).

Results: * Slower to detect Z among items with similar features (List 2 – angular
features) compared to dissimilar features (List 1 – curved features).

notes:

based on feature theory you should find that searching for the letter Z in a pile of letters with angular features takes longer than if it were among letters with rounded features this is because it becomes difficult to distinguish whether the features detected or that of the letter Z or that of the letter N v or W

Question 6

Feature Detection Theory

Distinctive features

Answer 6

Distinctive features: features that help to discriminate
between two patterns.

when learning our alphabets as children, children sometimes confuse letters that look similar like E&F or O and Q or M&N or K&X, however if children are taught the distinctive feature that helps one discern one letter another by highlighting the feature in red ink children are faster to learn letter discrimination even after the highlighting is removed

problems:

• Does not take spatial relationships into account.
• Detecting individual features can be inadequate for
  recognizing some patterns.

the problem with feature detection is that objects such as the letter T and the + have the same features a lowercase B&P share similar features

how do we distinguish between the two? what seems to matter is not just the features of an object but also the relation between these features

Question 7

structural theory

Biederman’s Recognition by Components Model (1987)

Answer 7

Biederman’s Recognition by Components Model (1987)

• A Structural theory
  * Involves features and the arrangement of features.
• All objects are constructed from a small number of 3-
  Dimensional shapes referred to as GEONS

notes:

Structural theories focus on how features are combined one such structural theory is called recognition by components which suggests that it is not just the features that matter for recognition but how the features combine

furthermore unlike feature detection theory which does not specify how many in which features are used for recognition, the recognition by components theory proposes that objects can be recognized based on a subset of 36 GEONS or shapes

the limitation of recognition by components theory is that it does not explain how come we can tell a granny Smith apple from a golden delicious apple or a gala apple?

the components in the way these components are arranged are the same for all these apples yet apple farmers would be able to distinguish between the variety of apples

perhaps recognition is more than just the components of an object and how they are put together

Question 8

problems with structural theory

Answer 8

Relying on features and how they combine is not
enough to explain how we can distinguish specific
members of a category.

• E.g., a granny smith apple versus a gala apple

Question 9

the nature of perception

Answer 9

Perception: Conscious experiences as a result of sensory stimulation.

characteristics:

Modifiable: can change with experience

our perceptions are influenced by our experiences, knowledge and memory since our experiences can impact perceptions, if our experience is changed this can modify our perception

• Results from a reasoning process: knowledge, memory, and experience
  influences perception
• Reciprocal relationship between perception and action

lastly there is a reciprocal relationship between perception and action, when we are moving within our environment or taking actions upon an object the sensory information is changing and with it our perception

Question 10

bottom-up processing

Answer 10

Bottom-Up Processing
* Also referred to as data-driven processing.
* Process of building a whole image from a set of features.

Question 11

top-down processing

Answer 11

Prior knowledge and expectations influence perception and
pattern recognition in the absence of (or even despite)
sensory input.

• Recognition when bottom-up information is ambiguous.
• Speeds pattern recognition when patterns are in their usual
  context.

Question 12

top-down processing

Word Superiority Effect (Reicher, 1969)

Answer 12

Procedure:
1. Brief presentation of a word (e.g., WORK) or a non-word (OWRK) or a
letter (e.g., K)
2. Asked: “Was there a D or K in the display?

Results:
Greater accuracy recognizing a letter presented rapidly when it is part of
a word rather than when it is presented alone or as a non-word!

Question 13

the challenges of designing a perceiving machine

Answer 13

Perceiving machines have difficulty with:

1. Solving the inverse projection problem
2. Recognizing hidden or blurred objects
3. Achieving viewpoint invariance
4. Recognizing scenes

Question 14

THE CHALLENGES OF DESIGNING A
PERCEIVING MACHINE

INVERSE PROJECTION PROBLEM

Answer 14

1. Inverse projection problem: When there is the SAME image on the retina
   from various objects (e.g., rectangular paper, tilted trapezoid), how do you
   determine what that object is?

Question 15

THE CHALLENGES OF DESIGNING A
PERCEIVING MACHINE

. Recognizing hidden or blurred objects:

Answer 15

2. Recognizing hidden or blurred objects: When objects are obscured or
   blurred, computers have difficulty with recognition.

Question 16

THE CHALLENGES OF DESIGNING A
PERCEIVING MACHINE

3) Viewpoint Invariance:

Answer 16

Computers have difficulty with recognizing the
same object from different viewpoints.

Computers have difficulty with recognizing both photos as the
same person if they are not front-on faces.

Computers can distinguish between two front-on faces

Question 17

THE CHALLENGES OF DESIGNING A
PERCEIVING MACHINE

recognizing scenes

Answer 17

4. Recognizing Scenes: Computers have difficulty perceiving a scene

Scene: real-world environment with items that are meaningfully organized
with each other and with the background.

Question 18

information for human perception

Answer 18

Human Perception: Involves both bottom-up and top-down processing.

Bottom-up processing: perception is based on sensory information from
the environment. Process is also referred to as data-driven processing.

Top-down processing: prior knowledge and experience influences
perception.

notes:

Question 19

INFORMATION FOR HUMAN PERCEPTION

Answer 19

TOP-DOWN PROCESSING

see example on slide

notes: Our experiences help us perceive the blob in the figure A l different ways in different scenes because of top down processing

for instance in figure B although the image is blurred we can rely on our prior knowledge of human form and the function of the table to interpret the same BLOB as some object on the table perhaps it’s a cup

in figure C the same BLOB is presented but within the context of being at the bottom of a person’s leg thus we perceive the BLOB as a shoe

in figure D once again our knowledge of the context in the image influences our perception of the BLOB to be a car and a person

Question 20

a demonstration of top down processing

Answer 20

A B C
12 13 14

Very quickly read the first and second line did you read it as ABC and 12/13/14 do you notice anything interesting about these two rows?

notice the second item in the top row and the second item in the bottom row are identical yet you recognize them to be different items one was recognized to be the letter B whereas in the bottom row it was probably recognized as the digit 13

why? well in the first row the second item is surrounded by letters A and C this context probably influenced your recognition for the second item

in the bottom row the numbers 12 and 14 influenced your recognition of the second item that is you identified it as a digit

in other words top down processing occurred since your prior knowledge of letters and numbers had influenced your recognition of the stimulant

Question 21

a demonstration of top down processing

image of a man

Answer 21

now look at this image what do you see this image this second image is ambiguous it can be perceived in more than one way either man or woman looking in a mirror if you report seeing a man you may have been influenced by prior knowledge in particular the prior presentation of a man influenced your perception of the ambiguous image to be that of a man

however what would happen if I had shown you an image of a lady looking in a mirror at time 1 but probably would have happened is that you would have perceived the ambiguous image to be that of a woman

since our recognition of the ambiguous image is influenced by what we had previously encountered this is an example of top down process is influencing our response

Question 22

INFORMATION FOR HUMAN PERCEPTION

Answer 22

Hearing Words in a Sentence: acoustic signal is often continuous. Hearing
individual words requires the ability to segment speech.

continous acoustic signal (see image)

notes:

the acoustic Signal is the pressure changes in the air and the acoustic signal for speech sounds are created by air being pushed from the lungs through the vocal tract

if you look at the acoustic signal on the screen when someone says speech segmentation you will notice that the acoustic signal is continuous furthermore it’s difficult to determine the start and end of this word speech as well as the start and ending of the word segmentation yet we’re able to perceive that there are 2 words because of our ability to segment speech in two distinct words

Question 23

speech segmentation

Answer 23

The ability to tell when one word in a conversation ends and the next one begins is a phenomenon called speech segmentation

The fact that a listener familiar only with English and another listener familiar with Spanish can receive identical sound stimuli but experience different perceptions means that each listener’s experience with language (or lack of it!) is influencing his or her perception

he continuous sound signal enters the ears and triggers signals that are sent toward the speech areas of the brain (bottom-up processing); if a listener understands the language, their knowledge of the language creates the perception of individual words (top-down processing).

Question 24

INFORMATION FOR HUMAN PERCEPTION

Answer 24

Speech segmentation: discriminate words in a conversation based on

Context/sentence used
* Meaning of the word
* Knowledge of word structure to assess transitional probabilities

notes:

speech segmentation is the discrimination of words and speech and our ability to perceive words in speech involves top down influences such as context or even meaning and prior knowledge and also bottom up processing is also involved that is the processing of auditory sensory information

and even with background noise you are still able to discriminate words in a conversation often because of top down influences

Question 25

INFORMATION FOR HUMAN PERCEPTION

Answer 25

Transitional Probabilities: Likelihood that one sound follows another
sound (based on our knowledge of that language).

• Pretty Baby: “pre” is followed by “tty” -> one word!
• Pretty Baby: “tty” is not followed by “ba” -> belong to different words!

notes:

speech segmentation or the ability to detect words in speech is influenced like I mentioned by top down processes such as prior knowledge and the retrieval of this prior knowledge to help us identify words in speech

in addition we rely on statistical learning or the process of learning what it’s called transitional probabilities

for instance if we have extensive knowledge of spoken English we would have learned that the likelihood that the sounds pre and t make one word because we know that the sound for the word pretty exists

however our experiences with spoken English we also know that T ba is not word so we wouldn’t combine these two sounds together rather we know that they belong to different words in that case in this case we had segmented these speech sounds into identifiable words pretty and baby

Question 26

transitional probabilities

Answer 26

While segmentation is aided by knowing the meanings of words, listeners also use other information to achieve segmentation. As we learn a language, we are learn- ing more than the meaning of the words

Without even realizing it we are learn- ing transitional probabilities—the likelihood that one sound will follow another within a word. For example, consider the words pretty baby. In English it is likely that pre and ty will be in the same word (pre-tty) but less likely that ty and ba will be in the same word (pretty baby).

Every language has transitional probabilities for different sounds, and the pro- cess of learning about transitional probabilities and about other characteristics of language is called statistical learning. Research has shown that infants as young as 8 months of age are capable of statistical learning.

Question 27

conceptions of object perception

Answer 27

1. Theory of Unconscious Inference
2. Gestalt Laws of Organization
3. Regularities in the environment
4. Bayesian Inference

Question 28

CONCEPTIONS OF OBJECT PERCEPTION

An early idea about how people use information was proposed by 19th-century physicist and physiologist Hermann von Helmholtz (1866/1911).

Answer 28

Theory of Unconscious Inference: Helmholtz proposed that image on
the retina is ambiguous and that some perceptions are from
unconscious assumptions that occur rapidly.

Helmholtz’s question was, How does the perceptual system “decide” that this pattern on the retina was created by overlapping rectangles? His answer was the likelihood principle, which states that we perceive the object that is most likely to have caused the pattern of stimuli we have re- ceived.

This judgment of what is most likely occurs, according to Helmholtz, by a process called unconscious inference, in which our perceptions are the result of unconscious assumptions, or inferences, that we make about the environment.

Thus, we infer that it is likely that Figure 3.14a is a rectangle covering another rectangle because of experiences we have had with similar situations in the past

Question 29

CONCEPTIONS OF OBJECT PERCEPTION

gestalt

Answer 29

Gestalt Principles of Organization:

1) Good continuation: * Points when connected create a smooth or straight line -> belong together

we don’t perceive two curved pieces (see photo)

2) Pragnanz * Aka principle of good figure or principle of simplicity states:

• Every stimulus pattern is seen in such a way that the resulting structure is as simple as possible.

3) principle of similarity: Similar items appear as part of the same group

Question 30

CONCEPTIONS OF OBJECT PERCEPTION

Answer 30

Perception influenced by bottom-up and top-down processes. However,
it’s proposed that bottom-up processes overrides top-down processes.

1) top-down processes: Perceive W and M due to
Knowledge of letters

2) Perceive two vertical lines andobject in-between due to principle
of good continuation

see image

Question 31

CONCEPTIONS OF OBJECT PERCEPTION

regularities of the environment into account

Modern perceptual psychologists take experience into account by noting that certain char- acteristics of the environment occur frequently. For example, blue is associated with open sky, landscapes are often green and smooth, and verticals and horizontals are often associ- ated with buildings. These frequently occurring characteristics are called regularities in the environment. There are two types of regularities: physical regularities and semantic regularities.

Answer 31

Regularities of the environment: characteristics of the
environment that frequently occur.

• Physical regularities: are regularly occurring physical properties of the environment. For example, there are more vertical and horizontal orientations in the environment than oblique (angled) orientations. This occurs in human-made environments (for example, buildings contain lots of horizontals and verticals) and also in natural environ- ments (trees and plants are more likely to be vertical or horizontal than slanted)

It is therefore no coincidence that people can perceive horizon- tals and verticals more easily than other orientations, an effect called the oblique effect

Another physical regularity is illustrated by Figure 3.23a, which shows indentations created by people walking in the sand. But turning this picture upside down, as in Figure 3.23b, trans- forms the indentations into rounded mounds. Our perception in these two situations has been explained by the light-from-above assumption: We usually assume that light is coming from above, because light in our environment, including the sun and most ar- tificial light, usually comes from above (Kleffner & Ramachan- dran, 1992). Figure 3.23c shows how light coming from above and from the left illuminates an indentation, leaving a shadow on the left. Figure 3.23d shows how the same light illuminates a bump, leaving a shadow on the right. Our perception of illu- minated shapes is influenced by how they are shaded, combined with the brain’s assumption that light is coming from above.
One of the reasons humans are able to perceive and recog- nize objects and scenes so much better than computer-guided robots is that our system is adapted to respond to the physical characteristics of our environment, such as the orientations of objects and the direction of light. But this adaptation goes beyond physical characteristics. It also occurs because, as we saw when we considered the multiple personalities of a blob (page 67), we have learned about what types of objects typi- cally occur in specific types of scenes.

Question 32

regularities of the environment into account

semantic regularities

Answer 32

Semantic regularities are the characteristics associated with the func- tions carried out in different types of scenes.

ne way to demonstrate that people are aware of semantic regularities is simply to ask them to imagine a particular type of scene or object, as in the following demonstration.

Most people who have grown up in modern society have little trouble visualizing an of- fice or the clothing section of a department store. What is important about this ability, for our purposes, is that part of this visualization involves details within these scenes. Most people see an office as having a desk with a computer on it, bookshelves, and a chair. The department store scene contains racks of clothes, a changing room, and perhaps a cash register. What did you see when you visualized the microscope or the lion? Many people report seeing not just a ingle object, but an object within a setting. Perhaps you perceived the microscope sitting on a lab bench or in a laboratory and the lion in a forest, on a savannah, or in a zoo. The point of this demonstration is that our visualizations contain information based on our knowledge of different kinds of scenes.

This knowledge of what a given scene typically contains is called a scene schema, and the expectations created by scene schemas contribute to our ability to perceive objects and scenes.

Question 33

CONCEPTIONS OF OBJECT PERCEPTION

Answer 33

Physical regularities: regularly occurring physical properties

1) Oblique effect: easier to perceive horizontal & verticals than other orientations

2) Uniform connectedness: Objects defined by areas of uniform texture or colour

3) Homogenous colours: within object same colour

4) Light-from-above heuristic: light in the natural environment is assumed to come
from above us.

Question 34

CONCEPTIONS OF OBJECT PERCEPTION

semantic regularities:

Answer 34

Semantic regularities: regularly occurring functions within a
scene that give the scene meaning.

Scene schema: knowledge of what is usually
in a particular scene.

Question 35

Although people make use of regularities in the environment to help them perceive, they are often unaware of the specific information they are using. This aspect of perception is similar to what occurs when we use language. Even though we aren’t aware of transitional probabilities in language, we use them to help perceive words in a sentence. Even though we may not think about regularities in visual scenes, we use them to help perceive scenes and the objects within scenes.

Answer 35

–

Question 36

CONCEPTIONS OF OBJECT PERCEPTION

bayesian

Answer 36

Bayesian inference: Thomas Bayes proposed that estimating the
probability of an outcome is based on

1. Prior probability: initial belief about the probability of an
   outcome.
2. Likelihood: extent that evidence is consistent with the
   outcome.

notes:

➤ Figure 3.24 These graphs present hypothetical probabilities to illustrate the principle behind Bayesian inference. (a) Mary’s
beliefs about the relative frequency of having a cold, lung disease, and heartburn. These beliefs are her priors. (b) Further data indicate that colds and lung disease are associated with coughing, but heartburn is
not. These data contribute to the likelihood. (c) Taking the priors and likelihood together results in the conclusion that Charles’s cough is probably due to a cold.

Question 37

Comparing the Four Approaches

Now that we have described four conceptions of object perception (Helmholtz’s un- conscious inference, the Gestalt laws of organization, regularities in the environment, and Bayesian inference),

here’s a question: Which one is different from the other three? A

Answer 37

The approaches of Helmholtz, regularities, and Bayes all have in common the idea that we use data about the environment, gathered through our past experiences in perceiving, to determine what is out there. Top-down processing is therefore an important part of these approaches.

The Gestalt psychologists, in contrast, emphasized the idea that the princi-
ples of organization are built in. They acknowledged that perception is affected
by experience but argued that built-in principles can override experience, thereby assigning bottom-up processing a central role in perception.

Question 38

NEURONS AND KNOWLEDGE ABOUT THE
ENVIRONMENT

theory of natural selection and experience dependent plasticity

Answer 38

Theory of Natural Selection: characteristics that help with
survival will be passed on.

notes:

When we described physical regularities in the environment, we mentioned that horizon- tals and verticals are common features of the environment (Figure 3.22), and behavioral experiments have shown that people are more sensitive to these orientations than to other orientations that are not as common (the oblique effect; see page 74). It is not a coincidence, therefore, that when researchers have recorded the activity of single neurons in the visual cortex of monkeys and ferrets, they have found more neurons that respond best to horizon- tals and verticals than neurons that respond best to oblique orientations (Coppola et al., 1998; DeValois et al., 1982). Evidence from brain-scanning experiments suggests that this occurs in humans as well (Furmanski & Engel, 2000).

Why are there more neurons that respond to horizontals and verticals? One possible answer is based on the theory of natural selection, which states that characteristics that enhance an animal’s ability to survive, and therefore reproduce, will be passed on to future generations. Through the process of evolution, organisms whose visual systems contained neurons that fired to important things in the environment (such as verticals and horizon- tals, which occur frequently in the forest, for example) would be more likely to survive and pass on an enhanced ability to sense verticals and horizontals than would an organism with a visual system that did not contain these specialized neurons. Through this evolutionary process, the visual system may have been shaped to contain neurons that respond to things that are found frequently in the environment.
Although there is no question that perceptual functioning has been shaped by evolu- tion, there is also a great deal of evidence that learning can shape the response properties of neurons through the process of experience-dependent plasticity that we introduced in Chapter 2 (page 34).

Question 39

NEURONS AND KNOWLEDGE ABOUT THE
ENVIRONMENT

experience - dependnet plasticity

Answer 39

Experience-Dependent Plasticity: experiences shape the
nervous system.

• FFA for face processing* FFA for complex stimuli (e.g., Greebles)* Greater brain responses with greater experience with the stimuli

In Chapter 2, we described Blakemore and Cooper’s (1970) experiment in which they showed that rearing cats in horizontal or vertical environments can cause neurons in the cat’s cortex to fire preferentially to horizontal or vertical stimuli. This shaping of neural responding by experience, which is called experience-dependent plasticity, provides evidence that experience can shape the nervous system.

Question 40

PERCEPTION AND ACTION: BEHAVIOUR

movement facilitates perception

Answer 40

• Movement helps with perception of the object

Although movement adds a complexity to perception that isn’t there when we are sitting in one place, movement also helps us perceive objects in the environment more accurately. One reason this occurs is that moving reveals aspects of objects that are not apparent from a single viewpoint.

For example, consider the “horse” in Figure 3.28. From one viewpoint, this object looks like a metal sculpture of a fairly normal horse (Figure 3.28a). However, walking around the horse reveals that it isn’t as normal as it first appeared (Figures 3.28b and 3.28c). Thus, seeing an object from different viewpoints provides added information that results in more accurate perception, especially for objects that are out of the ordinary, such as the distorted horse.

Question 41

PERCEPTION AND ACTION: PHYSIOLOGY

(what and where streams)

In a classic experiment, Leslie Ungerleider and Mortimer Mishkin (1982) studied how re- moving part of a monkey’s brain affected its ability to identify an object and to determine the object’s location. This experiment used a technique called brain ablation—removing part of the brain.

Ungerleider and Mishkin presented monkeys with two tasks: (1) an object discrimi- nation problem and (2) a landmark discrimination problem.

Answer 41

Object discrimination is impaired when the “WHAT/PERCEPTION”
area is lesioned

Landmark discrimination is impaired when the “WHERE/HOW
PERCEPTION” area is lesioned

Question 42

PERCEPTION AND ACTION: PHYSIOLOGY

dorsal pathway

Answer 42

Dorsal Pathway: Combines vision
with action

• Patient D.F.

Ventral stream damage: Impaired orientation judgment

Dorsal stream intact * good action performance

Question 43

PERCEPTION AND ACTION: PHYSIOLOGY

mirror neurons

Answer 43

Mirror Neurons are neurons in the premotor cortex that
respond when
* Carrying out an action oneself
* observing others carry out the same action

Question 44

Possible function of mirror neurons

Answer 44

Possible function of mirror neurons
* To help understand another animal’s actions and react to them
appropriately

Question 45

reflection questions

Answer 45

1.Discuss the inverse projection problem using your own example.

2.What are mirror neurons?

3.What is the association between perception and action?

Question 46

Biederman states that all objects are constructed from _________.

Answer 46

geons

Question 47

We perceive coiled rope as one item rather than multiple curved pieces because of a gestalt principle known as:

Answer 47

good continuation

Question 48

What part of the brain is part of the dorsal pathway for object perception?

Answer 48

parietal lobe

Question 49

The example of Crystal running on the beach and having coffee later illustrates how perception can change based on new information, how perception can be based on principles that are related to past experiences, how perception is a process, and how perception and action are connected.

Question 50

We can easily describe the relation between parts of a city scene, but it is often challenging to indicate the reasoning that led to the description. This illustrates the need to go beyond the pattern of light and dark in a scene to describe the process of perception.

Question 51

Attempts to program computers to recognize objects have shown how difficult it is to program computers to perceive at a level comparable to humans. A few of the difficulties facing computers are (1) the stimulus on the receptors
is ambiguous, as demonstrated by the inverse projection problem; (2) objects in a scene can be hidden or blurred; (3) objects look different from different viewpoints; and (4) scenes contain high-level information.

Question 52

Perception starts with bottom-up processing, which involves stimulation of the receptors, creating electrical signals that reach the visual receiving area of the brain. Perception also involves top-down processing, which is associated with knowledge stored in the brain.

Question 53

Examples of top-down processing are the multiple personalities of a blob and how knowledge of a language makes it possible to perceive individual words. Saffran’s experiment has shown that 8-month-old infants are sensitive to transitional probabilities in language.

Question 54

The idea that perception depends on knowledge was proposed by Helmholtz’s theory of unconscious inference.

Question 55

The Gestalt approach to perception proposed a number of laws of perceptual organization, which were based on how stimuli usually occur in the environment.

Question 56

Regularities of the environment are characteristics of the environment that occur frequently. We take both physical regularities and semantic regularities into account when perceiving.

Question 57

Bayesian inference is a mathematical procedure for determining what is likely to be “out there”; it takes into account a person’s prior beliefs about a perceptual outcome and the likelihood of that outcome based on additional evidence.

Question 58

Of the four approaches to object perception—unconscious inference, Gestalt, regularities, and Bayesian—the Gestalt approach relies more on bottom-up processing than the others. Modern psychologists have suggested a connection between the Gestalt principles and past experience.

Question 59

One of the basic operating principles of the brain is that it contains some neurons that respond best to things that occur regularly in the environment.

Question 60

Experience-dependent plasticity is one of the mechanisms responsible for creating neurons that are tuned to respond
to specific things in the environment. The experiments in which people’s brain activity was measured as they learned about Greebles supports this idea. This was also illustrated in the experiment described in Chapter 2 in which kittens were reared in vertical or horizontal environments.

Question 61

Perceiving and taking action are linked. Movement of an observer relative to an object provides information about the object. Also, there is a constant coordination between perceiving an object (such as a cup) and taking action toward the object (such as picking up the cup).

Question 62

Research involving brain ablation in monkeys and neuropsychological studies of the behavior of people with brain damage have revealed two processing pathways in the cortex—a pathway from the occipital lobe to the temporal lobe responsible for perceiving objects, and a pathway from the occipital lobe to the parietal lobe responsible for controlling actions toward objects. These pathways work together to coordinate perception and action.

Question 63

Mirror neurons are neurons that fire both when a monkey or person takes an action, like picking up a piece of food, and when they observe the same action being carried out by someone else. It has been proposed that one function of mirror neurons is to provide information about the goals or intentions behind other people’s actions.

Question 64

Prediction, which is closely related to knowledge and inference, is a mechanism that is involved in perception, attention, understanding language, making predictions about future events, and thinking.