Recognition - Lecture 6 - Personal

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1

Recognition

Advanced Cognitive Psychology

PSY 341


Fall 2004

2

Overview


Pattern recognition


Object recognition


Face recognition


Memory recognition


Categorization

3

Recognition


in general


Identifying and classifying information you
have paid attention to


Developmental speaking, identifying,
classifying, labeling, grouping,
categorizing, recognizing are easy to learn
and to teach


but how do we study these
processes?


Learning to read


is this a recognition
process?

4

Pattern Recognition


The process by which we match an incoming
stimulus with stored representations (in memory)
for the purpose of identification


Bottom up and top down processing are both
involved


View
-
based model of pattern recognition = whole
item is compared to image of whole item in
memory


Structural
-
description
-
based model of pattern
recognition = item is “broken” into fundamental
shapes and the set of shapes is compared to
combinations of shape images in memory


Testing these models


use distorted stimuli

5

Structural
-
Description Based Models


We compare patterns to a structural description in
memory;


Features of pattern


Relationships among the features


Images stored in memory are visually or spatially
the same as the pattern being recognized


Orientation or view of the pattern is not important


Examples:


Pandemonium Model
-

demons


Marr’s model


primal sketchs & 2 ½ D sketches


Recognition
-
by
-
Components (RBC)
-

geons

6

View
-
Based Models


Patterns are recognized as wholes and
comparisons are made to whole images in
memory


Recognition depends on the orientation of
the pattern or the perspective of the
viewer


Match must be perfect or pattern must be
rotated until a match is found in memory


Examples:


Template Matching


Tarr and Pinker study (1989)

7

Type of Processing and Recognition


Structural
-

and View
-
Based Models


bottom up processing


Evidence for Top Down Processing?


Word Superiority Effect


Really a combination of bottom up and top down
processing


Scene Superiority Effect


McClelland and Rumelhart Model (1981)


connectionist model


Two

System Views of Object Recognition

8

Face Recognition


Features vs. Whole Faces


Are faces "special"?
-

http://www.msnbc.msn.com/id/5970906/site/newswe
ek/


Farah, Wilson, Drain, and Tanaka (1998)


Wenger & Ingvalson (2003)


signal detection
explanation



Inverted Faces



Visual recognition deficits


Prosopagnoia


"50 First Dates"


Alexia
-

words


Object Agnosia


everyday objects


9

Memory Recognition


Recognition of items (objects, faces, words, pictures, etc.)
previously experienced or studied


How are these studies conducted?


Study list


Test list


targets and distractors


Signal detection paradigm


how results are summarized


Hits = target recognized as from study list


False Alarm = distractor recognized as from study list


Correct Rejection = subject says distractor not from study list


Miss = subject says target not from study list


Discrimination (sensitivity) = being able to recognize targets even
in the presence of distractors


Response Bias = tendency to say "everything is a target" (liberal)
or "everything is a distractor" (conservative)

10

Categorization


Concept = mental representation of a
category serving multiple functions, one of
which allows for determination of whether
it belongs to the class


Category = set of entities picked out by
the concept


Types of Categories


Natural categories


Artifact categories


Nominal kinds


Adhoc categories

11

Category Membership


Similarity
-
Based Approaches


bottom up


The Classical View


The Prototype Approach


The Exemplar Approach




Explanation
-
Based Approaches


top down