Recognition

Visual Recognition Sensory Registration Feature Analysis

Patterns are constructed from features activated by visual inputs.

Shape Construction

Feature Analysisscene

textureobject

geons(parts)

feature

Visual Recognition Sensory Registration Feature Analysis Shape Construction

Comparison Input patterns are compared with patterns in memory.

Response A match is found and associated patterns in memory are

activated to create a meaningful representation of the world (perception/consciousness).

Selection & Integration The new representation is integrated into an

object/scene representation that is used to direct action.

Stages Of Recognition Feature Analysis Stage.

Comparison Stage.

Response Stage.

Selection & Integration Stage.

Vision Hearing

Occipital Cortex Temporal Cortex

Medial temporal Cortex:Limbic system + thalamus + surrounding

cortex

Temporal Cortex Prefrontal cortex

Stages of Recognition Process Comparison Stage

Input patterns are compared with patterns in memory.

Response Stage A match is found and associated patterns in memory

are activated to create a meaningful representation of the world (perception/consciousness).

Selection & Integration Stage The new representation is integrated into an

object/scene representation that is used to direct action.

Stages of Recognition Process Comparison Stage

Multiple patterns for the same input may be constructed. Each pattern is part of a different pathway to recognition.

Logogens compare input patterns with patterns in memory.

Response Stage Selection & Integration Stage

Redundant pathways in word recognition

dog

/dahg/

/ahg/

dog

/d/

og

d

c

a

b

a. Visual whole word

c,b. Auditory whole word

e,f,b. Letter-sound

e

e

f

f/dawg/

b

Stages of Recognition Process Comparison Stage

Multiple patterns for the same input may be constructed. Each pattern is part of a different pathway to recognition.

Masked priming reveals form effects when words share same pattern that provide evidence of the letter sequence pathway.

Logogens compare input patterns with patterns in memory.

Response Stage Selection & Integration Stage

Priming When two inputs are presented in

succession, the effect of one on the perception of the other is called priming. A facilitory effect is call (positive) priming and

an inhibitory effect is called negative priming. The effect of the first input on the second is

called (forward) priming and the effect of the second word on the first is called (backward) priming.

Priming Tasks & Measures Verbal report of what is seen.

Accuracy Choice reaction time. For example,

press the right button if the string is a word and the left button if it is a nonword. Reaction time & Accuracy

Naming. Read word you see aloud. Voice Onset Latency

Masked and Unmasked Primes

CAT

Presented

Observed

Unmasked:

CAT DOG

DOG

Presented

Observed

Backward Masked:

XXX DOGDOG

CATXXXX

Presented

Observed

Forward Masked:

CAT DOGDOG

XXXXXXX

Types of Priming Unmasked. For example, 60 millisecond

word prime immediately precedes target. Both prime and target are visible.

Masked. For example, 400 millisecond mask (XXXX) immediately precedes prime, which immediately precedes target. Only mask and target are visible.

Priming Relationships Masked primes activate

perceptual relationships (form priming). Shared onsets are effective primes, e.g., bell –

book, stray – stroke. Priming is cross-modal, so huevo primes wave in

bilinguals. Semantic/associative relationships

cat primes dog Boeing primes 747

Masked primes only operate over short, unfilled intervals.

Redundant pathways in word recognition

dog

/dahg/

/ahg/

dog

/d/

og

d

c

a

b

a. Visual whole word

c,b. Auditory whole word

e,f,b. Letter-sound

e

e

f

f/dawg/

b

Stages of Recognition Process Comparison Stage

Multiple patterns for the same input may be constructed. Each pattern is part of a different pathway to recognition.

Masked priming reveals form effects when words share same pattern that provide evidence of the letter sequence pathway.

Masked auditory priming provides evidence of the auditory whole-word pathway.

Logogens compare input patterns with patterns in memory.

Response Stage Selection & Integration Stage

Priming Relationships Masked primes activate

perceptual relationships (form priming). Shared onsets are effective primes, e.g., bell –

book, stray – stroke. Priming is cross-modal, so huevo primes wave in

bilinguals. Semantic/associative relationships

cat primes dog Boeing primes 747

Masked primes only operate over short, unfilled intervals.

Redundant pathways in word recognition

dog

/dahg/

/ahg/

dog

/d/

og

d

c

a

b

a. Visual whole word

c,b. Auditory whole word

e,f,b. Letter-sound

e

e

f

f/dawg/

b

Stages of Recognition Process Comparison Stage

Multiple patterns for the same input may be constructed. Each pattern is part of a different pathway to recognition.

Masked priming reveals form effects when words share same pattern that provide evidence of the letter sequence pathway.

Masked auditory priming provides evidence of the auditory whole-word pathway.

Word superiority effect reveals the visual whole-word pathway. A briefly presented letter is more likely to be perceived in the context

of a word than by itself. E/O versus READ/ROAD Logogens compare input patterns with patterns in memory.

Response, Selection, & Construction Stage Decision Stage

Redundant pathways in word recognition

dog

/dahg/

/ahg/

dog

/d/

og

d

c

a

b

a. Visual whole word

c,b. Auditory whole word

e,f,b. Letter-sound

e

e

f

f/dawg/

b

Stages of Recognition Process Feature Analysis Stage Comparison Stage

Multiple patterns for the same input may be constructed. Each pattern is part of a different pathway to recognition.

Masked priming Word superiority effect Frequency effect reveals visual whole-word pathway.

Briefly presented high frequency words more likely to be seen than low frequency words or nonwords.

Logogens compare input patterns with patterns in memory.

Response, Selection, & Construction Stage Decision Stage

Redundant pathways explanation of frequency effect

dog

/dahg/

/ahg/

dog

/d/

og

d

c

a

b

a. Visual whole word

c,b. Auditory whole word

e,f,b. Letter-sound

e

e

f

f/dawg/

b

Stages of Recognition Process Feature Analysis Stage Comparison Stage

Multiple patterns for the same input may be constructed. Each pattern is part of a different pathway to recognition.

Masked priming Word superiority effect Frequency effect reveals visual whole-word pathway. Whole-word pathway makes skilled reading possible.

When asked to detect Ts, readers miss many in high frequency words, e.g., the.

Logogens compare input patterns with patterns in memory.

Response, Selection, & Construction Stage Decision Stage

Evidence of Whole-Word Pathway

Aoccdrnig to rscheearch at an Elingsh uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoatnt tihng is taht the frist and lsat ltteer is at the rghit pclae. The rset can be a toatl mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae we do not raed ervey lteter by it slef but the wrod as a wlohe.

Stages of Recognition Process Feature Analysis Stage Comparison Stage

Multiple patterns for the same input provide different pathways to recognition.

Logogens compare input patterns with patterns in memory.

Response Stage Selection Stage

Logogen Theory The brain is a continuously sensitive

receiver. When the match between an input an pattern in memory exceeds some criterion, perception of the pattern occurs.

Other names for logogens Perceptrons Demons (“Pandemonium”) Neural Net Connectionist Model

Logogen

boy boy

boy

boy

criterion

activationlevel

Stages of Recognition Process Feature Analysis Stage Comparison Stage

Multiple patterns for the same input provide different pathways to recognition.

Logogens compare input patterns with patterns in memory.

Repetition effect

Response Stage Selection & Integration Stage

Repetition effect

boy boyboy

b__ _o_ __y

boy

Activation from successive partialmatches can accumulate so repeatinga briefly presented item causes it tobe perceived more clearly.

Stages of Recognition Process Feature Analysis Stage Comparison Stage Response Stage

Logogens are part of semantic network. When a logogen responds associated

representations are also activated. Masked and unmasked semantic priming

reveals the spread of activation. Selection & Integration Stage

Responsescene

textureobject

geons(parts)

feature

point, triangle

star

wheel, compass

Priming Relationships Masked primes activate

Perceptual relationships (form priming).

Semantic/associative relationships cat primes dog Boeing primes 747

Masked primes only operate over short, unfilled intervals.

Priming Relationships Unmasked primes activate

semantic relationships, such as boy – girl. Unmasked primes can be effective

over long, filled intervals.

Explanation of semantic priming

cat dog

cat

cat Activation spreads among semantically related logogens

Nonvisual semantic information may influence visual recognition

Logogen system

dog

Motor Planning

dig

don

dot

/

dawg//ahg/

dog

/d/

og

d

Decision stage

/dawg/ /d/ /ahg/

d

dot

don

dig

cat

Stages of Recognition Process Comparison Stage Response Stage

Logogens are part of semantic network. Selection & Integration Stage

Some of the activated representations are combined into a single larger representation

Words into sentences Objects into a scene

Selection & Integrationscene

textureobject

geons(parts)

feature

Spatial context in visual recognition The elements of a scene

semantically prime each other Memory is a part of scene analysis

So we may construct a meaningful scene out of meaningless parts

Perception and recognition can not be separated into successive processing stages

Stages of Recognition Process Feature Analysis Stage Comparison Stage Response Stage

Logogens are part of semantic network. Selection and Integration Stage

A structural description is used to combine individual representations into a larger meaningful representation.

Structural Description A structural description describes

the relative locations of different categories of objects that are identified through feature representations. Faces, scenes

Structural Description A structural description describes the

relative locations of different categories of objects that are identified through feature representations.

Structural descriptions make it possible to recognize an infinite number of things categorically, hence semantically.

Structural Description A structural description describes the relative

locations of different categories of objects that are identified through feature representations.

Structural descriptions make it possible to recognize an infinite number of things categorically, hence semantically.

The categorical structural descriptions that are used to construct representations are part of procedural memory but the instance representations constructed with the structural descriptions are part of declarative memory.

Types of Visual Agnosia

LGN ofThalamus

Retina

OccipitalCortex

SurroundingVisual Cortex

MesialTemporalSubcortex

Inabilityto accessmemory

associativeagnosia

Inabilityto integrate

featuressimultagnosia

Response Selection& Integration

Feature Analysis & Comparison: Top-DownPerceptual Processing

Bottom upPerceptualProcessing

Summary Comparison between representation of

perceptual input and representations in memory Redundant pathways increase probability of match

Response includes multiple associated representations Priming, agnosia, and apraxia provide evidence of

specific pathways and associations Selection of context-appropriate

representation is integrated with structural description Orients you to place