Cognition, Culture and Categories

Ray Larson & Warren Sack

IS202: Information Organization and Retrieval

Fall 2001

UC Berkeley, SIMS

lecture author: Warren Sack and Marti Hearst

Cognitive Science

• 10/30/01 – AI, knowledge representation and common sense

• 11/01/01 – Computational Linguistics, Cognitive Psychology and Lexical Knowledge

• 11/06/01 – AI and information extraction• 11/08/01 – Linguistics, Philosophy,

Psychology, categories, and cognition

Last Time: Information Extraction

• A short history: AI Story Understanding, SAM, and FRUMP

• Basic Techniques: Lexical analysis, name recognition, syntax, scenario, coreference, inference, template

• Evaluation: MUC-3 to MUC-7

• What else can you do with an IE system? SpinDoctor and PLUM

SpinDoctor: Categorizing News Stories by

Ideological Point of View

George LakoffPh.D., Linguistics, Indiana University, 1966. Taught at Harvard University from

1965-69, at the University of Michigan from 1969-71, spent 1971-72 at the Center for Advanced Study in the Behavioral Sciences at Stanford, before coming to Berkeley in 1972. His current research covers many areas of Conceptual Analysis within Cognitive Linguistics: (i) The nature of human conceptual systems, especially metaphor systems for concepts such as time, events, causation, emotions, morality, the self, politics, etc. This also includes the study of such systems in other languages and their manifestations in linguistic form; (ii) The development of Cognitive Social Science, which applies ideas of Cognitive Semantics to the Social Sciences; (iii) The implications of Cognitive Science for Philosophy, in collaboration with Mark Johnson, Chair of Philosophy at the University of Oregon; (iv) Neural foundations of conceptual systems and language, in collaboration with Jerome Feldman, of the International Computer Science Institute, seeking to develop biologically-motivated structured connectionist systems to model both the learning of conceptual systems and their neural representations; (v) The cognitive structure, especially the metaphorical structure, of mathematics, in collaboration with Rafael Núñez.

George Lakoff

Selected Publications• Metaphors We Live By (with Mark Johnson) Univ. of Chicago

Press. 1980.• Women, Fire, and Dangerous Things. University of Chicago

Press. 1987.• More Than Cool Reason. (with Mark Turner) Univ. of Chicago

Press. 1989.• Moral Politics. University of Chicago Press. 1996.• Philosophy in The Flesh. Basic Books, 1999.• Where Mathematics Comes From: How the Embodied Mind

Brings Mathematics into Being. (with Rafael Núñez). Basic Books. 2000.

The Fairy Tale of the Just WarCast of characters: A villain, a victim, and a hero. The victim and the hero may be the

same person.The scenario: A crime is committed by the villain against an innocent victim

(typically an assault, theft, or kidnapping). The offense occurs due to an imbalance of power and creates a moral imbalance. The hero either gathers helpers or decides to go it alone. The hero makes sacrifices; he undergoes difficulties, typically making an arduous heroic journey, sometimes across the sea to a treacherous terrain. The villain is inherently evil, perhaps even a monster, and thus reasoning with him is out of the question. The hero is left with no choice but to engage the villain in battle. The hero defeats the villain and rescues the victim. The moral balance is restored. Victory is achieved. The hero, who always acts honorably, has proved his manhood and achieve glory. The sacrifice was worthwhile. The hero receives acclaim, along with the gratitude of the victim and the community.

The fairy tale has an asymmetry built into it. The hero is moral and courageous, while the villain is amoral and vicious. The hero is rational, but though the villain may be cunning and calculating, he cannot be reasoned with. Heroes thus cannot negotiate with villains; they must defeat them. The enemy-as-demon metaphor arises as a consequence of the fact that we understand what a just war is in terms of this fairy tale.

(from Lakoff, Metaphor and War: The Metaphor System Used to Justify War in the Gulf, 1991)

Metaphorical DefinitionThe most natural way to justify a war on moral grounds is to fit this fairy tale

structure to a given situation. This is done by metaphorical definition, that is, by answering the questions: Who is the victim? Who is the villain? Who is the hero? What is the crime? What counts as victory? Each set of answers provides a different filled-out scenario.

As the gulf crisis developed, President Bush tried to justify going to war by the use of such a scenario. At first, he couldn't get his story straight. What happened was that he was using two different sets of metaphorical definitions, which resulted in two different scenarios:

The Self-Defense Scenario: Iraq is villain, the US is hero, the US and other industrialized nations are victims, the crime is a death threat, that is, a threat to economic health.

The Rescue Scenario: Iraq is villain, the US is hero, Kuwait is victim, the crime is kidnap and rape. The American people could not accept the Self-Defense scenario, since it amounted to trading lives for oil. The day after a national poll that asked Americans what they would be willing to go to war for, the administration settled on the Rescue Scenario, which was readily embraced by the public, the media, and Congress as providing moral justification for going to war.

(from Lakoff, Metaphors and War: The Metaphor System Used to Justify War in the Gulf, 1991)

Associated Metaphors

• Clauzewitz’s Metaphor: War is politics pursued by other means

• War as violent crime

• War as a competitive game

• War as medicine

• The State-as-Person System

Associated Metonym

• The ruler-for-state metonym

Objectivist views• Thought is mechanical manipulation of symbols• The mind is an abstract machine• Symbols get their meaning from correspondences to the

external world• Symbols are internal representations• Abstract symbols stand in correspondence with the external

world independent of the interpreting organism• The human mind is a mirror of nature• Human bodies play no role in characterizing concepts• Thought is abstract and disembodied• Exclusively symbolic machines are capable of thought• Thought can be broken down into simply “building blocks”• Thought is defined by mathematical logic.

Lakoff’s views• Thought is embodied• Thought is imaginative• Thought has gestalt properties• Thought has an ecological structure• Conceptual structure can be described using cognitive

models that have the above properties• The theory of cognitive models incorporates what was

right about the traditional view of categorization, meaning, and reason, while accounting for the empirical data on categorization and fitting the new view overall;. (pp. xiv-xv)

ICM: Idealized Cognitive Models

Four types of cognitive models• Propositional: characterize structure• Image schematic: characterize structure• Metaphoric: characterize mappings that use

structure• Metonymic: characterize mappings that use

structure.All cognitive models are embodied either

directly or indirectly.

Category Structure

• Defining Category Membership– Necessary and Sufficient Conditions– Properties of Categorization

• Characteristic Features• Centrality/Typicality• Basic Level Categories

Defining Category Membership

• Necessary and Sufficient Conditions:– Every condition must be met.– No other conditions can be required.

• Example: A prime number:– An integer divisible only by itself and 1.

Source: Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.

• Example: mother– A woman who has given birth to a child.

Can category membership be defined?

What are the necessary and sufficient conditions for something to be a game?

Definition of Game• Famous example by Wittgenstein

– Classic categories assume clear boundaries defined by common properties (necessary and sufficient conditions)

• Counterexample: “Game”– No common properties shared by all games

• card games, ball games, Olympic games, children’s games• competition: ring-around-the-rosie• skill: dice games• luck: chess

– No fixed boundary; can be extended to new games• video games

• Alternative: Concepts related by Family Resemblances

Properties of Categorization• Family Resemblance

– Members of a category may be related to one another without all members having any property in common.

• Instead, they may share a large subset of traits.• Some attributes are more likely given that others have been

seen.

– Example: feathers, wings, twittering, ...• Likely to be a bird, but not all features apply to “emu”• Unlikely to see an association with “barks”

Properties of Categorization• Centrality

– Example: Prime Numbers• Definition: An integer divisible only by itself and 1• Examples: 1, 2, 3, 5, 7, 11, 13, 17, …

– A very clear-cut category. Or is it?• Can one number be “more prime” than another?

– Centrality: some members of a category may be “better examples” than others.

• Example: robins vs. chickens vs. emus

Properties of Categorization

• Characteristic Features– Perceived degree of category membership has to

do with which features define the category.– Members usually do not have ALL the necessary

features, but have some subset.– Those members that have more of the central

features are seen as more central members.– People have conceptions of typical members.

Testing for Centrality/Typicality

• Ask a series of questions, compare how long it takes people to answer.– True or false:

• An apple is a fruit.• A plum is a fruit.• A coconut is a fruit.• An olive is a fruit.• A tomato is a fruit.

– Rosch and Mervis: • The more features a fruit shares with the other fruits, the

more typical a member of the class it is.

Characteristic Features

– Is a cat on a mat a cat?– Is a dead cat a cat?– Is a photo of a cat a cat?– Is a cat with three legs a cat?– Is a cat that barks a cat?– Is a cat with a dog’s brain a cat?– Is a cat with every cell replaced by a dog’s cells a

cat?

Properties of Categorization

• Basic-level Categories:– Categories are organized into a hierarchy from the

most general to the most specific, but the level that is most cognitively basic is “in the middle” of the hierarchy

• Basic-level Primacy:– Basic-level categories are functionally primary with

respect to factors including ease of cognitive processing (learning, reasoning, recognition, etc).

Basic Level Categories

• Brown 1958, 65, Berlin et al., 1972, 73• Folk biology:

– unique beginner: plant, animal– life form: tree, bush, flower– generic name: pine, oak, maple, elm– specific name: Ponderosa pine, white pine– varietal name: western Ponderosa pine

• No overlap between levels• Level 3 is basic

– corresponds to genus

Characteristics of Basic-level Categories

Language– People name things more readily at basic level.– Name learned earliest in childhood.– Languages have simpler names at basic level.– Sounds like the “real name”. – Name used more frequently.

• Strange to call a dime a coin, a metal object

– Names used in neutral context.• There’s a dog on the porch.• There’s a terrier on the porch.

Characteristics of Basic-level Categories

Concepts– Things perceived more holistically at the basic level

(rather than by parts).– People interact with basic and more specific levels

similarly.– Things are remembered more readily at basic level.– Folk biological categories correspond accurately to

scientific biological categories only at the basic level.

Three Psychologically Primary Levels

SUPERORDINATE animal furnitureBASIC LEVEL dog chairSUBORDINATE terrier rocker

• Children take longer to learn superordinate• Superordinate not associated with mental images

or motor actions/Google demo• How related to

– Hyponymy– Hyperonymy

Categories vs. Words

• Necessary and Sufficient conditions for Mother?

• mother(A,B) -> female(A), gave-birth-to(A,B), same-species(A,B), …,

• What about:• Birth mother vs. adoptive mother• Rearing role vs. biological role• Surrogate mother• Cloning

• Need to distinguish between the word used and the underlying concept(s) it stands for.

Summary– Processes of categorization underlie many of the

issues having to do with information organization– Categorization is messier than our computer systems

would like– Human categories have graded membership,

consisting of family resemblances.• Family resemblance is expressed in part by which subset of

features are shared• It is also determined by underlying understandings of the

world that do not get represented in most systems

– Basic level categories, as well as subordinate and superordinate categories, seem to be cognitively real.

Are ICM just Frames, Scripts, or Schemas?

• Minsky’s frames (Minsky, 1975) are only propositional models; they do not include any of the “imaginative models” – metanymic, metaphoric, and image schematic.

• Demo: TRIND: Triplets and Demons Frame-based Programming language.

Image Schemas

Examples (from Johnson, The Body in the Mind, 1987)

• CONTAINER– Structural elements: INTERIOR,

BOUNDARY, EXTERIOR– Sample metaphors: the visual field is

understood as a CONTAINER: “come into sight,” “go out of sight”

Image Schemas (continued)

• PART-WHOLE schema– Structural elements: WHOLE, PARTS, and

a CONFIGURATION– Sample metaphors: families, spouses,

divorce as “splitting up”

Image Schemas (continued)

• LINK schema– Structural elements: ENTITY, CENTER,

PERIPHERY– Same metaphors: what is important is

considered to be “central.”

Image Schemas (continued)

• SOURCE-PATH-GOAL schema• Structural elements: SOURCE,

DESTINATION, PATH, DIRECTION• Examples: purposes are understood in terms

of destinations, and achieving a purpose is understood as passing along a path from start to destination. Thus, one may “go a long way towards” achieving one’s goals, or one may get “sidetracked,” find someone in one’s “way,” etc.

Experiential Basis of Metaphors

• Each metaphor has a source domain, a target domain, and a source-to-target mapping. To show that a metaphor is “natural” in that it is motivated by the structure of our experience, we need to answer three questions.

• Example: MORE IS UP; LESS IS DOWN: the crime rate keeps rising, the stock has fallen, etc.

Foucault on Borges

This passage quotes “a certain Chinese encyclopedia” in which it is written that “animals are divided into: (a) belonging to the emperor, (b) embalmed, © tame, (d) suckling pigs, (e) sirens, (f) fabulous, (g) stray dogs, (h) included in the present classification, (I) frenzied, (j) innumerable, (k) drawn with a very fine camelhair brush, (l) et certera, (m) having just broken the water pitcher, (n) that from a long way off look like flies.

(Foucault, The Order of Things, 1970)

Summary: Idealized Cognitive Models and the Possibility of a

Cognitive SemanticsFour types of cognitive models• Propositional: characterize structure• Image schematic: characterize structure• Metaphoric: characterize mappings that use

structure• Metonymic: characterize mappings that use

structure.All cognitive models are embodied either

directly or indirectly.

Next Time

• Controlled Vocabulary

• Information Architecture Assignment