Knowledge representation images and propositions
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Knowledge Representation --- Images and Propositions. Lecturer: Siyun Liu. Knowledge Structures. Mental Representation of Knowledge » declarative knowledge facts that can be stated knowing that procedural knowledge procedures that can be implemented knowing how .

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Knowledge representation images and propositions

Knowledge Representation--- Images and Propositions

Lecturer: Siyun Liu


Knowledge structures

Knowledge Structures

  • Mental Representation of Knowledge »

    • declarative knowledge

      • facts that can be stated

      • knowing that

    • procedural knowledge

      • procedures that can be implemented

      • knowing how


Knowledge representations

Knowledge Representations

  • External Representations »

  • Internal Representations »

Back


External representations

External Representations

  • Pictures »

  • Words »

  • The differences between picture representation and word representation »

Home


Picture representations

Picture Representations

  • The picture is relatively analogous to the real-world object it represents;

  • The picture shows concrete attributes (shape & relative size) that are similar to the features and spatial properties of the real-world object the picture represents.

  • Pictorial representations convey all features simultaneously

Home


Picture representation

Picture Representation

Home


Word representation

Word Representation

  • Words are symbolic representations

  • Words capture abstract and categorical information

  • Representations in words usually convey information sequentially

Home


Words are symbolic

Words Are Symbolic

  • 拉丁符号:Ç Ì Ñ Ô Ø à ã Ë Đ

  • 希腊符号:ΎξλζέΪΠΣΘςΰ

  • 希伯来语:בהלףץסכזא

  • 汉语:中国

Home


Pictures vs words

Pictures vs. Words

  • Neither form of representation actually retains all of the characteristics of what is being represented

  • Pictures and words represent relationships in different ways

Home


Internal representations

Internal Representations

  • Mental Images »

  • Propositions »

Home


Mental images

Mental Images

  • Definition »

  • Various Forms »

Home


Definition of mental images

Definition of Mental Images

  • The mental representation of things that are not currently being sensed by the sense organs;

    • It may represent things that have never been observed by your senses at any time;

    • It may represent things that do not exist at all.

Home


Various forms

Various Forms

  • Seeing ------ visual images »

    • seeing in the absence of a visual stimulus

    • not presently visible to the eyes

  • Hearing

  • Smell

  • Taste

Home


Mental imagery

Mental Imagery

  • Memory Codes of Mental Imagery »

  • Empirical Investigations of Imagery»

  • The nature of mental imagery »

    • Questions about mental images

      • What are images?

      • What kinds of properties do images have?

      • How are these like or unlike the properties that real pictures have?

  • Neuropsychological Findings »

Home


Memory codes of mental imagery

Memory Codes of Mental Imagery

  • The Dual-Coding Hypothesis »

  • The Relational-Organizational Hypothesis »

Home


The dual coding hypothesis

The Dual-Coding Hypothesis

  • Allan Paivio (1969, 1971)

    • We can use either verbal or imagined codes or both for representing information.

      • Verbal

        • Containing information about an item’s abstract, linguistic meaning

      • Imagined

        • Mental pictures of some sort that represent what the item looks like

    • Pictures and concrete words

      • Both verbal labels and visual images

    • abstract words

      • Only verbal label

Evidence1 for Dual-Coding

Home

Evidence2 for Dual-Coding


Evidence for dual coding

Evidence for Dual-Coding

  • Paivio (1965)

    • four lists of noun pairs

      • CC: concrete word vs. concrete word

        • Book vs. Table

      • CA: concrete word vs. abstract word

        • Chair vs. Justice

      • AC: abstract word vs. concrete word

        • Freedom vs. Dress

      • AA: abstract word vs. abstract word

        • Beauty vs. Truth

Continue…


Evidence for dual coding1

Evidence for Dual-Coding

  • Participants learnt one of four lists, then had a recall test

Continue…


Evidence for dual coding2

Evidence for Dual-Coding

  • Interpretations for results (1969)

    • When items are coded by both images and verbal labels, the chances of the learner’s retrieving them are obviously better.

      • If the learner forgets the verbal label, he or she might still access the visual images, or vice versa.

    • Items coded only by verbal labels are disadvantages

      • If the verbal label is forgotten or “misplaced”, the learner has less to go on.

Continue…


Evidence for dual coding3

Evidence for Dual-Coding

  • Interpretations for results (1969)

    • The first noun in a pair (“stimulus” noun) serves as a conceptual peg on which the second (“response”) noun is hooked.

    • The stimulus noun serves as a “mental anchor”, a place to which the representation of the response noun can be attached.

    • The imaginability of the first noun is particularly important in improving memorability

      • This is why recall in the CA condition was significantly higher than in the AC condition

Continue…


Evidence for dual coding4

Evidence for Dual-Coding

  • Interpretations for results

    • Whenever possible, participants spontaneously formed visual images of the noun pairs

      • The formation was easiest with concrete nouns

    • Visual imagery, unlike verbal labelling, increases as a function of concreteness.

      • The more concrete the noun, the richer the image and the more elaborated the internal code.

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Evidence for dual coding5

Evidence for Dual-Coding

  • Lee Brooks (1968)

    • Provided evidence that images are distinct from verbal materials or at least use different processes from those used by verbal materials.

    • Two types of tasks

      • visual task:

        • briefly presented a picture, answer questions about it

      • verbal task:

        • briefly presented a sentence, make judgment about it

    • Two types of responses

      • Visual: point to an answer

      • Verbal: saying “yes” or “no”

Continue…


Evidence for dual coding6

Evidence for Dual-Coding

  • Lee Brooks (1968)

    • Material 1 used in the experiment

      • Task for material 1

      • Findings for task 1

    • Material 2 used in the experiment

      • Task for material 2

      • Findings for task 2

Conclusion


Evidence for dual coding7

Evidence for Dual-Coding

A BIRD IN THE HAND IS NOT IN THE BUSH.

Start at the corner marked with a dot, and indicate whether or not each corner is at the extreme top or bottom.

For each word in the sentence above, indicate whether or not each word is a concrete noun.

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Evidence for dual coding8

Evidence for Dual-Coding

  • Participants responded in different ways

    • Verbal

      • Participants say “yes” or “no”

    • Spatial

      • Participants were given a response sheet on which the letters Y and N were printed in an irregular pattern, and were told to point to either a Y or an N in each row to indicate their response

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Evidence for dual coding9

Evidence for Dual-Coding

  • Task 1:

    • Participants took almost two and a half times longer when they responded by pointing than they did by responding verbally. Reason

  • Task 2:

    • Participants were faster to respond by pointing than they were to respond verbally. Reason

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Evidence for dual coding10

Evidence for Dual-Coding

  • It requires the formation of a visual image of an F.

    • The visual image probably has at least some picture-like qualities (spatial or visual), so a spatial or visually guided response (pointing) would be interfered with to a greater extend than would a verbal response.

    • The visual image is more disruptive of, and disrupted by, another spatial or visual type of task (pointing) than by a verbal kind of task (talking).

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Evidence for dual coding11

Evidence for Dual-Coding

  • Holding a sentence in memory (a verbal task) is easier to do with a concurrent visual/spatial task (such as pointing) than with another verbal task.

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Evidence for dual coding12

Evidence for Dual-Coding

  • Conclusion

    • Images and words use different kinds of internal codes (dual-coding hypothesis)

    • Visual images and words are separate codes Try it

      • Visual imagery interferes with other visual tasks

      • Verbal tasks interfere with other verbal tasks

      • Visual imagery does not interfere with verbal tasks

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Knowledge representation images and propositions 1335456

  • Which of the following tasks is (are) the hardest one(s)?

  • Imagine an elephant and at the same time try to draw a house.

  • Imagine the definition of “elephant” and at the same time write down a definition of short-term memory.

  • - Draw an elephant and at the same time provide a definition of short-term memory.

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The relational organizational hypothesis

The Relational-Organizational Hypothesis

  • Bower (1970b)

    • The relational-organizational hypothesis

      • An alternative to the dual-coding hypothesis

      • Imagery improved memory by producing more associations between the items to be recalled, rather than being richer than verbal labels

        • Individuals create a number of links or hooks between the information to remember and other information in paired-associates learning.

Home

Continue…


The relational organizational hypothesis1

The Relational-Organizational Hypothesis

  • Imagery facilitates the creation of a greater number of hooks that link the two to-be-remembered pieces of information

    • Bower (1970b) provided evidence to distinguish between the dual coding and the relational-organizational hypothesis

Evidence


Evidence for relational organizational hypothesis

Evidence for relational-organizational hypothesis

  • Three groups of participants with different instructions for a paired-associates learning task

    • G1: to rehearse aloud

    • G2: to construct two images that did not interact and were “separated in imaginal space”see here

    • G3: to construct an interactive scene of the two words in a pair see here

Continue…


Piano vs cigar

Piano vs. Cigar

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Dog vs bathtub

Dog vs. Bathtub

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Evidence for relational organizational hypothesis1

Evidence for relational-organizational hypothesis

  • Results

    • All participants recognized about 85% of the previously seen words, however,

      • G1: recalled 30% of the paired associates

      • G2: recalled 27% of the paired associates

      • G3: recalled 53% of the paired associates

Interpretations


Evidence for relational organizational hypothesis2

Evidence for relational-organizational hypothesis

  • If Dual-Coding hypothesis is correct

    • G2 = G3

      • Imagery simply led to more elaborated coding of the paired associates

  • However

    • G2 < G3

      • It is not imagery per se that helps memory

      • Rather, it is the way in which imagery is used

Continue…


Evidence for relational organizational hypothesis3

Evidence for relational-organizational hypothesis

  • Interacting images presumably create or suggest more links between the target information and other information, making the target information easier to retrieve

  • Evidence support for relational-organizational hypothesis

Home


Empirical investigations of imagery

Empirical Investigations of Imagery

  • Mental Rotation of Images

    • Shepard & Metzler (1971) »

    • Cooper & Shepard (1973) »

  • Images Scanning

    • Functional-equivalence hypothesis »

    • Image Scaling »

    • Image Scanning »

Home


Mental rotation of images

Mental Rotation of Images

  • Shepard & Metzler (1971)

    • They showed participants perspectives line drawings of three dimensional objects.

    • Participants were presented two drawings

      • The drawings depicted the same object but with one rotated by some degree. See here

        • Rotation was in a picture plane

        • Rotation was in depth

      • The drawings depicted mirror-image reversals

        • The objects were similar but not identical. See here

        • The mirror images were also sometimes rotated.

Findings


Mental rotation of images1

Mental Rotation of Images

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Mental rotation of images2

Mental Rotation of Images

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Mental rotation of images3

Mental Rotation of Images

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Mental rotation of images4

Mental Rotation of Images

  • The amount of time it took participants to decide if the two drawings depicted the same object or a mirror-image reversal was directly proportional to the angle of rotation between the drawings.

See Figure Here


Mental rotation of images5

Mental Rotation of Images

5

MeanRT (Sec)

0

0 20 40 60 80 100 120 140 160 180

Angle of rotation (degree)

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Mental rotation of images6

Mental Rotation of Images

  • Changes in manipulations

    • Materials

      • Rotation of letters

    • Procedure

      • Participants given a cue showing the orientation to which the test stimulus would be rotated, before the test stimulus appeared

Results


Mental rotation of images7

Mental Rotation of Images

Result


Knowledge representation images and propositions 1335456

Implications


Mental rotation of images8

Mental Rotation of Images

  • Participants’ performances were the same for all angles of rotation if the cues were presented early enough

    • 1000 msec before the test stimulus appeared

  • Participants were able mentally to rotate their images either clockwise or counterclockwise, depending on which direction led to a lesser angle.

Home

More questions


Mental rotation of images9

Mental Rotation of Images

  • Are participants in these experiments mentally rotating the whole stimulus, or are they looking only at certain parts?

  • Lynn Cooper (1975)

    • Used irregular polygons as materials ▶


Mental rotation of images10

Mental Rotation of Images

Continue…


Mental rotation of images11

Mental Rotation of Images

  • Two steps:

    • Participants were first trained to discriminate between original and mirror-image reflections of the polygons

    • Then they were shown either the original polygons or the reflections at different angles of rotation and were asked to determine whether the object depicted was the original or a reflection of the original.

Result


Mental rotation of images12

Mental Rotation of Images

Continue…


Mental rotation of images13

Mental Rotation of Images

  • The reaction times again increased linearly with the angle of rotation

  • The rate of rotation was the same for all the polygons, regardless of their complexity

    • Participants mentally rotated entire polygons

      • Treated the very simple polygons in exactly the same manner as they did the very complex ones

Home


Functional equivalence hypothesis

Functional-equivalence hypothesis

  • Although we do not construct images that are exactly identical to percepts, we do construct images that are functionally equivalent to percepts

  • These functionally equivalent images are analogous to the physical percepts they represent

Home

Apply to …


Functional equivalence hypothesis1

Functional-equivalence hypothesis

Red eye

Jump

Eat carrots

Short tail

Ect……

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Image scaling

Image Scaling

  • Seeing featural details of large objects is easier than seeing such details of small ones, and we respond more quickly to questions about large objects we observe than to questions about small ones we observe. Example

  • If imaginal representation is functionally equivalent to perception, participants also should respond more quickly to questions about features of imaginally large objects than to questions about features of imaginally small ones. Example

    • this prediction was confirmed

Home


Image scaling1

Image Scaling

  • The bigger the size, the more detail available

  • Even with visual imagery

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Image scaling2

Image Scaling

Judgments are faster for rabbits when they are next to smaller things

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Image scanning

Image Scanning

  • The visual images constructed and transformed by people are like real pictures in many ways.

    • People’s scanning of their visual images is in some ways similar to their scanning of actual pictures.

      • The greater the distance between two parts, the longer it takes to scan between them.

Evidence 1 for Image Scan

Home

Interesting wrinkles


Image scanning1

Image Scanning

  • Kosslyn (1973)

    • Procedure

      • Participants memorized a picture of an object (e.g., boat)

      • Then they created an image of that object in their mind

      • Participants were asked to focus on one part, then asked to look for another part on the boat and press a key

    • Rationale

      • If imagery, like perception, is spatial (i.e., analog), then it should take longer for participants to find parts that are located further from the initial point of focus See here

    • This was supported by the results

      • See also Kosslyn et al (1978)

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Image scanning2

Image Scanning

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Image scanning3

Image Scanning

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Image scanning4

Image Scanning

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Image scanning5

Image Scanning

  • Barbara Tversky (1981) ▶

    • People’s maps are systematically distorted in orienting and anchoring oddly shaped units

      • Use different heuristics, or rule of thumb

      • Follow the Principles of perceptual organization

  • Chambers and Reisberg (1992) ▶

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Image scanning6

Which is further west (north,east)?

Image Scanning

  • Draw a map of United States (China), put in several cities:

    • Seattle; Portland, Oregon; Carson City; Los Angeles; San Diego; Chicago; Boston; Portland, Maine; Philadelphia; New York; Washington, D. C. ▶

    • 北京,天津,石家庄,昆明,西安,济南,成都,上海,南京,杭州▶

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Image scanning7

Image Scanning

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Knowledge representation images and propositions 1335456

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Image scanning8

Image Scanning

  • Show participants an ambiguous figure ▶

  • Presented the actual drawing for only about 5 seconds

    • Enough time to form an image but not enough time to “reverse” the figure

Continue…


Image scanning9

Image Scanning

  • Two different instructions

    • Some participants were told it was a duck

    • Others were told it was a rabbit

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Image scanning10

Image Scanning

  • Participants were presented with a pair of duck/rabbits

  • To choose which had actually been presented

or

A

B

A

C

Findings…


Image scanning11

Image Scanning

  • When participants thought they were imaging a duck, they were well above chance at detecting the difference between (A) and (B);

  • Exactly the opposite pattern emerged for those who had formed an initial image of a rabbit.

Reason


Image scanning12

Image Scanning

  • People paid more attention to the region they took to be the creature’s “face” and less to the back of the creature’s head.

  • People who form images of the same physical stimulus, but who give different construals or meanings to the stimulus, actually form different images.

Continue…


Image scanning13

Image Scanning

  • Language hints in constructing images

    • Front-back

    • Furrier

    • Cleaner-dirtier; fatter-thinner

    • Better-worse; smarter-dumber

  • Imagery created depends a lot on the nature of the task at hand

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The nature of mental imagery

The nature of mental imagery

  • Principles of Visual Imagery »

  • Critiques of Mental Imagery Research and Theory »

  • The significance of knowing whether people use imagery as a means of coding information »

Home


Principles of visual imagery

Principles of Visual Imagery

  • Finke’s (1989) review

    • Describe the fundamental nature and properties of visual images

    • Five Principles

      • Implicit Encoding ▶

      • Perceptual Equivalence ▶

      • Spatial Equivalence ▶

      • Transformational Equivalence ▶

      • Structural Equivalence ▶

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Implicit encoding

Implicit Encoding

  • Images are places from which some information can be obtained, even if that information was never intentionally stored

    • Imagery can be used to answer questions for which you probably don’t have a directly stored answer

      • Tracing an F in Brook’s (1968) task

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Perceptual equivalence

Perceptual Equivalence

  • Many of the same kinds of internal processes used in mental visualization are used in visual perception as well

    • Study by Farah (1985) ▶

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Perceptual equivalence1

Perceptual Equivalence

  • Participants were asked to form an image of a letter

    • H or T

  • When H was presented later at a low level of contrast

    • Participants were better at detecting the letter compared to the one participants had not form an image

  • Imagery can “prime” the visual pathway used in detecting an actual stimulus

    • Visual imagery is as perceptual “anticipation”

      • The visual system is getting ready to actually to see something

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Spatial equivalence

Spatial Equivalence

  • The spatial arrangement of the elements of a mental image corresponds to the way objects or their parts are arranged on actual physical surfaces or in an actual physical space

    • Study by Kosslyn et al

    • Map scanning study by Nancy Kerr (1983) ▶


Spatial equivalence1

Spatial Equivalence

  • Two groups of participants

    • Congenitally blind participants

      • Learned the map by feeling objects

    • Sighted participants

  • Task

    • Imagined moving a dot from one object to another

  • Findings

    • The greater the distance between objects, the longer it took both blind and sighted participants to scan

    • Visual imagery has spatial properties

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Transformational equivalence

Transformational Equivalence

  • Imagined transformations and physical transformations exhibit corresponding dynamic characteristics and are governed by the same laws of motion

    • Example: mental rotation

    • Other kinds of transformations will work with images in much the same way they work with real objects as well

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Structural equivalence

Structural Equivalence

  • Images are organized and assembled

    • The structure of mental images corresponds to that of actual perceived objects, in the sense that the structure is coherent, well organized, and can be reorganized and reinterpreted.

      • The larger the object, the more time it would take to look over or to draw

      • Visual images are formed, not all at once, but in pieces that are assembled into a final rendition

    • Study by Kosslyn et al (1983) ▶


Structural equivalence1

Structural Equivalence

  • Participants were asked to form images of pictures that differed in amount of detail ▶

    • It took participants about one and a third times as long to form an image of the detailed pictures as it did other participants to form images of outline drawings

  • The greater the complexity of the conceived structure of the object, the longer it takes to assemble an image of it

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Structural equivalence2

Structural Equivalence

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Critiques of mental imagery research and theory

Critiques of Mental Imagery Research and Theory

  • Tacit knowledge and demand characteristics ▶

  • The picture metaphor ▶

  • Propositional theory ▶

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Tacit knowledge and demand characteristics

Tacit knowledge and demand characteristics

  • Pylyshyn (1981)

    • The results from many imagery studies reflect participants’underlying and implicit, tacitknowledge and beliefs about the task rather than their construction and manipulation of visual images.

      • Participants’ scanning time is proportional to distance scanned, because they know that the amount of time it takes to physically scan between two points in a visual display depends on distance and because they expect the experiment to demand this kind of performance.

        • Knowledge and expectation

Continue…


Tacit knowledge and demand characteristics1

Tacit knowledge and demand characteristics

  • Finke (1989)

    • Move a cup from one end of a desk to another end

  • Two options to do the task

    • Slide the cup across the desk

    • Pick up the cup and place it in the new location

Continue…


Tacit knowledge and demand characteristics2

Tacit knowledge and demand characteristics

  • Demand characteristics of tasks

    • Some tasks make it obvious to participants how the participants ought to perform

    • The instructions, the tasks themselves, or something else about the situation cues the person on how to behave

Continue…


Tacit knowledge and demand characteristics3

Tacit knowledge and demand characteristics

  • Experimenter expectancy effects

    • Participants try to please and may behave artificially just to perform in ways they believe will satisfy the experimenter

      • Intons-Peterson (1983) conducted several imagery studies

        • Had some experimenters believe the results would turn out in one way

        • Had other experimenters believe the opposite

        • Results: participants performed as experimenters expected them to

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The picture metaphor

The picture metaphor

  • Much discussion of an analogy between pictures and images

  • Pylyshyn (1973)

    • Pictures and images differ in several ways

      • You can physically look at a picture without first knowing what it’s a picture of

      • You cannot “look” at an image unless you first know what it is

        • Images are internal constructions formed with some intention in mind

Continue…


The picture metaphor1

The picture metaphor

  • Pictures and images are disrupted, and disruptable, in different ways.

    • You can cut a photograph in half, with the result that arbitrary parts of the objects depicted disappear.

    • Images are organized more meaningfully, and when they fade, only the meaningful parts disappear.

Continue…


The picture metaphor2

The picture metaphor

  • Images seem more easily distorted by the viewer’s interpretations than are pictures or photographs

    • Carmichael et al (1932)

      • Presented participants with patterns ▶

      • Participants’ later reproductions of the patterns were distorted in accordance with the label initially provided

Continue…


The picture metaphor3

The picture metaphor

Word list1

Word list2

Stimulus Figures

Diamond in a rectangle

Curtains in a window

Bottle

Stirrup

Crescent moon

Letter C

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The picture metaphor4

The picture metaphor

  • Nickerson & Adams (1979)

    • People make many errors when trying to reproduce their images of familiar objects

      • Draw a penny

        • How much information is on your penny?

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Propositional theory

Propositional theory

  • Propositional theorists believe there is a single code, neither visual nor verbal but propositional in nature, that is used to store and mentally represent all information

    • Propositions are a means of specifying relationships between different concepts

Continue…


Propositional theory1

Propositional theory

  • Pylyshyn (1973)

    • All information is mentally represented and stored by propositions.

      • Participants in visual imagery experiments might look as if they were consulting or manipulating internal visual representations, but they would actually be using internal propositional representations, the same kind of representations that underlie their processing of verbal material.

        • Sentences or stories

Continue…


Propositional theory2

Propositional theory

  • Kosslyn (1976)

    • Tested the association strength between animals and their physical attributes

      • “claws” are more strongly associated with “cat” than “head”

    • When people did not use imagery, they were faster to verify that cats had claws

      • High association value, small visual part of a cat

    • The higher the association value, the more propositions relating the two items, then the faster the verification time

Continue…


Propositional theory3

Propositional theory

  • Kosslyn (1976)

    • When participants reported having used imagery to do the task, their reaction times went in the opposite direction.

      • They were faster to verify visually larger parts with low association values than visually smaller parts with higher association values

      • Using imagery results in performance that propositional theory does not predict

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The significance

The significance

  • It is crucial to explaining how they carry out a variety of cognitive tasks

  • Make good predictions about when they use what code

  • Predict when they are likely to be able to do things easily, and when they won’t

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Neuropsychological findings

Neuropsychological Findings

  • Lateralization of function »

    • Patients withidentified lesions

    • Split-brain patients

  • Recent findings »

  • Other findings»

Home


Neuropsychological findings1

Neuropsychological Findings

  • Right hemisphere

    • visual memory and visual perception

      • Representing and manipulating knowledge of a visuospatial nature

  • Left hemisphere

    • verbal memory and verbal comprehension

      • Representing and manipulating verbal and other symbol-based knowledge

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Neuropsychological findings2

Neuropsychological Findings

  • Both animals and humans show that both hemispheres may be partially responsible for image task performance

    • Brain activation of humans »


Brain activation in mental rotation

Brain Activation in mental rotation

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Neuropsychological findings3

Neuropsychological Findings

  • Roland & Friberg (1985)

    • Participants performed three cognitive tasks while their cerebral blood flows were being monitored

    • Tasks were mentalarithmetic, memory scanning of an auditory stimulus, and visual imagery (visualizing a walk through a familiar neighbourhood)

Findings


Neuropsychological findings4

Neuropsychological Findings

  • Massive activation in the parts of the brain important for visual processing of information during the imagery task

    • Mostly in the occipital lobe and other posterior regions

  • During the other two tasks, there were no such increases in cerebral blood flow to those parts

Continue…


Neuropsychological findings5

Neuropsychological Findings

  • Farah (1988)

    • Replicated the results using ERPs ▶

      • Measuring electrical activity in the brain

  • Same results were found by many other investigators

    • Kosslyn & Ochsner, 1994

    • Miyashita, 1995

    • Kosslyn, Thompson, Kim, & Alpert, 1995

Continue…


Neuropsychological findings6

Neuropsychological Findings

  • ERPs were higher

  • Occipital cortex

  • Temporal cortex

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Neuropsychological findings7

Neuropsychological Findings

  • The specific area of the occipital lobe showing maximal activation differed depending on whether the image created was small, medium, or large

  • More findings ▶


Knowledge representation images and propositions 1335456

Imagery neurons

Continue…


A double dissociation

A double dissociation

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Propositional theory4

Propositional Theory

  • We do not store mental representations in the form of images; rather our mental representations more closely resemble the abstract form of a proposition

  • A proposition ▶


Propositional theory5

Propositional Theory

  • The meaning underlying a particular relationship among concepts

  • Both images and verbal statements are mentally represented in terms of their deep meanings (as propositions), not as specific images or statements.

Continue…


Propositional theory6

Propositional Theory

  • Look at the picture ▶

    • Create a proposition

      • [in (dog, bathtub)]

    • Predicate calculus

      • Expressing the underlying meaning of a relationship

      • Describe any kind of relationship

        • Actions, attributes, positions, class memberships

Continue…


Synthesizing images and propositions

Synthesizing Images and Propositions

  • Mental representations may take any of the three forms (Johnson-Laird’s Mental Models)

    • Propositions

      • fully abstracted representations of meaning

    • Mental models

      • knowledge structures that individuals construct to understand and explain their experiences

    • Images

      • much more specific representations, which retain many of the perceptual features of particular objects, viewed from a particular angle, with the particular details of a given instantiation

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Synthesizing images and propositions1

Synthesizing Images and Propositions


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