PSYCH 147 REVIEWER takes the distance of the farther object into account, so it is
CHAPTER 3: PERCEPTION perceived as its true, larger size.
THE NATURE OF PERCEPTION
perception- experiences resulting from stimulation of the
senses
-Her experience illustrates how perceptions can change, based
on added information (Crystal’s view became better as she got
closer to the umbrella), and how perception can involve a
process similar to reasoning or problem solving (Crystal figured
out what the object was based partially on remembering having
seen that umbrella the day before)
PERCEPTION STARTS AT THE RECEPTORS: BOTTOM-UP
PROCESSING
Bottom-Up Processing: Physiological
Bottom-up processing- processing that begins with
stimulation of the receptors
-sequence of events that occur after light reflected from a tree
stimulates the visual receptors in the eye. We saw that
stimulation of the receptors triggers a series of events in which
electrical signals are transmitted from the receptors toward the
brain.
-Perceiving a tree, or any other object, depends on activity
beyond the visual cortex, but the feature detectors’ response is
the rst step in the brain’s response to objects. Thus, when you
look at an object such as a tree, neurons in the visual cortex
that respond to specific orientations re to features of the tree,
such as the trunk and branches
Bottom-Up Processing: Behavioral size constancy—we tend to perceive objects as remaining the
-The idea that neurons fire to individual features of a tree same size even when they move to different distances
suggests that perhaps our perception of the tree is created by Perceiving Odor Intensity: Taking Sniffing Into Account
combining the information provided by the ring of many feature -Even though stronger sniffing causes more odor molecules to
detectors. A behavioral approach to this idea that perception stimulate the receptors, this did not influence the participants’
can be created by combinations of individual features has been odor intensity ratings
proposed by Irving Biederman -It is clear from these two very different examples that while
recognition-by-components (RBC)- theory, proposes that we perception may start at the receptors, it depends on additional
perceive objects by perceiving elementary features called sources of information as well.
geons. USING KNOWLEDGE: TOP-DOWN PROCESSING
Geons- perceptual building blocks that can be combined to Speech segmentation- Because of their knowledge of the
create objects language, they are able to tell when one word ends and the
-we can recognize an object if we are able to perceive just a next one begin
few of its geons -The fact that a listener familiar only with English and another
-We can also perceive objects even if portions of the geons are listener familiar with Spanish can receive identical sound stimuli
obscured but experience different perceptions means that each listener’s
principle of componential recovery—if we can recover (see) experience with language (or lack of it!) is influencing his or her
an object’s geons, we can identify the object. perception.
-ex. Of airplaine and covered flashlight Helmholtz’s Theory of Unconscious Influence
-RBC provides an example of bottom-up processing because theory of unconscious inference- which states that some of
its basic unit—the geon—is simple and because perceiving our perceptions are the result of unconscious assumptions that
simple geometric objects. we make about the environment.
BEYOND BOTTOM-UP PROCESSING -This theory was proposed to account for our ability to create
Perception Depends on Additional Information perceptions from stimulus information that can be seen in more
Top-down processing- processing that begins with a person’s than one way
prior knowledge or expectations *red and blue rectangle example
-can be involved in our ability to recognize objects based on likelihood principle- which states that we perceive the object
just a few geons, or when large portions of the object are that is most likely to have caused the pattern of stimuli we have
obscured received
-Another example of how top-down processing is involved in -Helmholtz therefore described the process of perception as
perceiving objects is illustrated in ● Figure 3.6, which is called being similar to the process involved in solving a problem. For
“the multiple personalities of a blob” perception, the problem is to determine which object has
-The blob shown in (a) is perceived as different objects caused a particular pattern of stimulation, and this problem is
depending on its orientation and the context within which it is solved by a process in which the observer applies his or her
seen. It appears to be an object on a table in (b), a shoe on a knowledge of the environment in order to infer what the object
person bending down might be.
Feedback signals- Signals such as this, that travel down from Unconscious influence- this process is unconscious^^^
higher centers to influence incoming signals, associated with a The Gestalt Laws of Organization
person’s knowledge and expectations, are being transmitted -perceptual organization- the way elements are grouped
down from higher levels in the brain together to create larger objects
-From the physiological point of view, therefore, perception of -The Gestalt psychologists proposed a number of laws of
an object is based on signals representing the object plus perceptual organization that indicate how elements in the
signals representing other aspects of the environment and environment are organized, or grouped together.
feedback signals representing prior knowledge or expectations law of good continuation- points that, when connected, result
in straight or smoothly curving lines are seen as belonging
CHAPTER 3: PERCEPTION perceived as its true, larger size.
THE NATURE OF PERCEPTION
perception- experiences resulting from stimulation of the
senses
-Her experience illustrates how perceptions can change, based
on added information (Crystal’s view became better as she got
closer to the umbrella), and how perception can involve a
process similar to reasoning or problem solving (Crystal figured
out what the object was based partially on remembering having
seen that umbrella the day before)
PERCEPTION STARTS AT THE RECEPTORS: BOTTOM-UP
PROCESSING
Bottom-Up Processing: Physiological
Bottom-up processing- processing that begins with
stimulation of the receptors
-sequence of events that occur after light reflected from a tree
stimulates the visual receptors in the eye. We saw that
stimulation of the receptors triggers a series of events in which
electrical signals are transmitted from the receptors toward the
brain.
-Perceiving a tree, or any other object, depends on activity
beyond the visual cortex, but the feature detectors’ response is
the rst step in the brain’s response to objects. Thus, when you
look at an object such as a tree, neurons in the visual cortex
that respond to specific orientations re to features of the tree,
such as the trunk and branches
Bottom-Up Processing: Behavioral size constancy—we tend to perceive objects as remaining the
-The idea that neurons fire to individual features of a tree same size even when they move to different distances
suggests that perhaps our perception of the tree is created by Perceiving Odor Intensity: Taking Sniffing Into Account
combining the information provided by the ring of many feature -Even though stronger sniffing causes more odor molecules to
detectors. A behavioral approach to this idea that perception stimulate the receptors, this did not influence the participants’
can be created by combinations of individual features has been odor intensity ratings
proposed by Irving Biederman -It is clear from these two very different examples that while
recognition-by-components (RBC)- theory, proposes that we perception may start at the receptors, it depends on additional
perceive objects by perceiving elementary features called sources of information as well.
geons. USING KNOWLEDGE: TOP-DOWN PROCESSING
Geons- perceptual building blocks that can be combined to Speech segmentation- Because of their knowledge of the
create objects language, they are able to tell when one word ends and the
-we can recognize an object if we are able to perceive just a next one begin
few of its geons -The fact that a listener familiar only with English and another
-We can also perceive objects even if portions of the geons are listener familiar with Spanish can receive identical sound stimuli
obscured but experience different perceptions means that each listener’s
principle of componential recovery—if we can recover (see) experience with language (or lack of it!) is influencing his or her
an object’s geons, we can identify the object. perception.
-ex. Of airplaine and covered flashlight Helmholtz’s Theory of Unconscious Influence
-RBC provides an example of bottom-up processing because theory of unconscious inference- which states that some of
its basic unit—the geon—is simple and because perceiving our perceptions are the result of unconscious assumptions that
simple geometric objects. we make about the environment.
BEYOND BOTTOM-UP PROCESSING -This theory was proposed to account for our ability to create
Perception Depends on Additional Information perceptions from stimulus information that can be seen in more
Top-down processing- processing that begins with a person’s than one way
prior knowledge or expectations *red and blue rectangle example
-can be involved in our ability to recognize objects based on likelihood principle- which states that we perceive the object
just a few geons, or when large portions of the object are that is most likely to have caused the pattern of stimuli we have
obscured received
-Another example of how top-down processing is involved in -Helmholtz therefore described the process of perception as
perceiving objects is illustrated in ● Figure 3.6, which is called being similar to the process involved in solving a problem. For
“the multiple personalities of a blob” perception, the problem is to determine which object has
-The blob shown in (a) is perceived as different objects caused a particular pattern of stimulation, and this problem is
depending on its orientation and the context within which it is solved by a process in which the observer applies his or her
seen. It appears to be an object on a table in (b), a shoe on a knowledge of the environment in order to infer what the object
person bending down might be.
Feedback signals- Signals such as this, that travel down from Unconscious influence- this process is unconscious^^^
higher centers to influence incoming signals, associated with a The Gestalt Laws of Organization
person’s knowledge and expectations, are being transmitted -perceptual organization- the way elements are grouped
down from higher levels in the brain together to create larger objects
-From the physiological point of view, therefore, perception of -The Gestalt psychologists proposed a number of laws of
an object is based on signals representing the object plus perceptual organization that indicate how elements in the
signals representing other aspects of the environment and environment are organized, or grouped together.
feedback signals representing prior knowledge or expectations law of good continuation- points that, when connected, result
in straight or smoothly curving lines are seen as belonging
