Categories and Concepts

Question 1

Category

Answer 1

set of things that are grouped together on the basis of something

Question 2

Concept

Answer 2

mental representation of a category

Question 3

You must…

Answer 3

remember previous experiences

recognize similarity

have a concept “lion”

Question 4

Concept increases processing efficiency for

Answer 4

Memory
Reasoning
Communication
Complex Concepts

Question 5

Cat

Answer 5

both a category and a concept

concept within category of animals
category that includes all the types of different cats

Question 6

Basic Level

Answer 6

neither too general nor specific

tends to be used in speaking and reasoning about categories
ex: airplane, apple, etc.

Question 7

Basic Level of Categorization

Answer 7

represented in language by a single word

in naming, we are likely to use the basic level

easier to explain what features are common to members of basic level categories than for other levels

Question 8

Inductive Inference

Answer 8

reaching a general conclusion based on specific examples
use examples to build up general rule

categorization is itself an inductive inference

Question 9

Deductive inference

Answer 9

reaching a conclusion about a specific instance, based on general principles

Question 10

Gelman and Markman

Answer 10

Shown flamingo
"bird feeds its babies mashed up food"
Shown Bat
"bat feeds its babies milk"
Shown blackbird
"what does this bird feed its babies?"

Question 11

Inductive inference from categories

Answer 11

85% of preschoolers guess blackbird feeds its babies mashed up food. Used category information, rather than perceptual similarity to make inference

Question 12

Three classes of theories

Answer 12

Classical, Probabilistic, Exemplar

Question 13

Classical Theory

Answer 13

Rules
category defined in terms of necessary and sufficient features

representation is abstract, does not store any information about specific exemplars

Question 14

Probabilistic Theory

Answer 14

Failure of classical theory led to proposal that category representation may be probabilistic rather than deterministic

Prototype theory: prototypes

Exemplar theory: individual instances

both based on idea of similarity

Question 15

Theory Theory

Answer 15

categories provide explanations for how things work in the world

center on causal relations between entities in the world

guide perception by leading us to believe that particular features are interesting and others are not

Question 16

Criticisms of Classical theory

Answer 16

defining features often can’t be found

you can often remove any particular feature and some object will still be a category member

Non-necessary features affect categorization

violation of any one defining feature does not seem to affect our categorization

Question 17

Ludwig Wittgenstein

Answer 17

What is a game?

for many categories there are no clear defining features

various members share various features, but there is no single feature that is necessary

Question 18

Challenges for Classical Theory

Answer 18

it is impossible to give adequate definitions

graded membership

typicality effects
(robin is more typical bird than a penguin)

Question 19

Family Resemblance

Answer 19

Wittgenstein proposed that members of a category have a family resemblance to each other

no defining features that one must have but there are common/typical features

membership is a matter of degree, not all or nothing

Question 20

Graded family membership

Answer 20

items are in a category, qualify based on necessary and sufficient rules

items are not in a category, do not meet the necessary and sufficient rules

Question 21

Typicality effects

Answer 21

Name fruit: most common ones (most typical) are named most frequently

Question 22

Prototype Theory

Answer 22

categories are represented by the average of all members of the category

items can be better or worse examples of a category

Question 23

Prototype Theory cont.

Answer 23

prototype need not exist in real world

category representation is abstract, does not store information about specific exemplars

graded category membership

Question 24

Posner & Keele

Answer 24

two prototypes created and never shown to the participants.
distortions of each prototype are created. Subjects learn to classify the distortions. New distortions, (variations of the old ones) were shown, then prototypes were shown

Question 25

Posner and Keele results

Answer 25

subjects were more likely to endorse the prototype as a category member than they were for a new distortion
Old (studied) distortions were classified just as well as the unseen prototype. Suggests that subjects store an average of their experiences

Question 26

Problems with Prototype Theory

Answer 26

assumes that information about individual instances is not stored. People do seem to store information about individual exemplars

Question 27

Exemplar thoery

Answer 27

concepts are represented by all of the exemplars that have been experienced

Category “bird” is represented by memories of all previous experiences of birds. When we categorize, we compare to all exemplars in memory

category representation is concrete

Question 28

Natural vs. Artifact

Answer 28

Natural: groupings that occur naturally (bird, trees)

Artifact: designed/invented (computers, sports cars)

Question 29

Stable vs. Ad-hoc

Answer 29

Stable: people generally agree on what goes into them, what the criteria of inclusion are

Ad-hoc: unstable categories defined for a special purpose or within a specific context

Question 30

What is a drunk?

Answer 30

knowledge based causal theory: late at night, someone jumps into pool fully clothed

concept of drunk involves a theory of impaired judgment which explains the man’s behavior so you induce he must be drunk

Question 31

Schema

Answer 31

large, complex units of knowledge that encode properties which are typical of instances of general categories and omit properties which are not typical of the categories

Question 32

Summary of Approaches to categorization

Answer 32

Classical theory: concepts have definitions

Prototype: summary representation for each category

Exemplar: no summary representation, concept is a collection of individual instances

Theory based: categories include causal explanations