Ch 8 categories and concepts
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Ch. 8: Categories and concepts. Concept and Knowledge. Topic: How do we store and manipulate a concept in the brain?. Concepts, beliefs and behavior. Concept/belief and action. Mother Teresa Timothy McVeigh (Oklahoma bomber) Ted Kaczynski (the unabomber) Osama bin Laden Mahatma Gandhi

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Concept and knowledge
Concept and Knowledge

  • Topic:

    • How do we store and manipulate a concept in the brain?

Concept belief and action
Concept/belief and action

  • Mother Teresa

  • Timothy McVeigh (Oklahoma bomber)

  • Ted Kaczynski (the unabomber)

  • Osama bin Laden

  • Mahatma Gandhi

  • Nelson Mandela

  • George Washington

  • 74 men and women died in Waco, TX

  • Bill Clinton

Psychiatric disorders
Psychiatric disorders

  • Anxiety disorder

    • Is created by an lingering belief on something threatening happens

  • Maniac depression

    • Disbelief on one’s ability, fate, etc.

Political language:

  • Compassionate conservative

    • support the rich but also, supposedly, generous to the poor.

  • Limousine liberal

    • extremely rich but appreciate liberal ideas.

  • War president

    • A president who deals with war.

  • Death tax

    • Inheritance tax

  • Pro-life

    • a political position against abortion

  • Pro-choice

    • a political position that supports abortion

  • Insurance premium

    • Insurance fee

  • Tax cuts

    • cutting taxes of one group and raising taxes for others

  • Stereotype

    • Ethnic conflicts

    Concept and memory
    Concept and memory?

    • Are they two different things?

    What is the structure of concept
    What is the structure of “concept”?

    This is the today’s topic.


    • Tell me what you see as accurately as possible.

    Why do you say hammer
    Why do you say “hammer”?

    • Why not “hand tool”?

    • Or why not the $15 hammer I bought in Wal Mart last Wednesday?

    • Why not “animal”?

    • Or why not “vegetable”?

    What is concept
    What is “concept”?

    • I don’t know

      • But maybe concept we have is related to the way we categorize things

    Concept categories
    Concept --> categories

    • In order to study “concept”, I’ll talk about “categories” .

    There are trillions of categories
    There are trillions of categories.

    • Animals, dogs, cats, birds, mammals, furniture, desks, chairs, tables, books, magazines…..

    • Trees, grass, weed, stones, rocks, sand, mountains, rivers,…..

    • Games, sports, hobbies, …

    • school, banks, shops, restaurants, supermarkets,

    Ad hoc categories
    Ad hoc categories philanthropists, sophists, aristocrats, workers, bankers, lawyers, accountants, teachers, students, disciples, masters, gurus, beggars, bigots,

    • People I adore, People I admire, People I hang around, People I need, People I avoid.

    • Things I love, Things I enjoy, Places I love, Food I hate, music I like, movies I enjoy

    • countries I want to visit, restaurants I avoid

    When we say dog what s going on in our mind
    When we say “dog,” what’s going on in our mind?

    • What is the mental representation of “categories”?

    • How do we distinguish in our mind

      • a dog from a cat?

      • a circle from a triangle?

    • What’s going on?

      • What is the structure?

      • What is the neural connections?


    • What determines “dog” vs. “cat” or “table” vs. “vegetable”, “game” vs. “sport”,…..

    Classical view
    Classical view

    • Necessary & sufficient rule

      • we store definitions.

    • Circle --> an area circumscribed by an equidistant curve.

    • Triangles --> an area circumscribed by three straight lines having three angles………..

    A circle of friends, Dupon circle, Columbus Circle, Circle line

    Bermuda triangles, triangle defense (Chicago Bulls)

    • Brother, sister, mother, father, uncle,

    • Some concepts may be organized with specific rules.

    • But how about other categories?

      • Game?

        • Basketball, softball, horse race, chess, a wheel of fortune, survivor, roulette, love affair, computer game, Super Mario?

      • furniture

        • desk, table, rug? Bed? Computer? TV?

    Concepts and categories
    Concepts and categories

    • Pink is basically red.

    • 99 is almost 100.

    • Orange is sort of yellow.

    • Austin is like Rome.

    • San Antonio is very much like Mexico.

    • Pita can be bread.

    Concepts and categories ii
    Concepts and categories II

    • Red is basically pink.

    • 100 is almost 99.

    • Yellow is almost orange.

    • Rome is like Austin.

    • Mexico is very much like San Antonio.

    • Bread can be pita.

    Which game is the best example of game
    Which game is the best example of “game”?

    • Baseball

    • Chess

    • Basketball

    • Politics

    • Football

    • Golf

    • One-night love affair

    • Snowboarding

    • Checker

    • Ping-Pong

    • Slot machine

    • Poker

    • Mahjong

    • Horse racing

    • NASCAR racing

    Fruit vs vegetable
    Fruit vs. Vegetable

    • Onion

    • Carrot

    • Pepper

    • Potato

    • Jalapeno

    • Cucumber

    • Bitter Melon

    • Spinach

    • Garlic

    • Ginger

    • Broccoli

    • Plantain

    • Lettuce

    • Cabbage

    • Pumpkin








    Grape fruit







    • Fruits  banana

      • Sweet, can eat without cooking, lots of vitamin, from tropical countries, soft, ripe quickly, easy to eat, kids love it, tasty, can bring it for hiking

    • Vegetables  carrot

      • Not sweet, not tasty, require some cooking, lots of vitamin, from anywhere, hard, stay long, kids don’t like it, hard

    Probabilistic view
    Probabilistic view

    • The boundaries of categories are fuzzy (probabilistically determined).

    • Some members are more probable than others.

    • But we are pretty sure about what “dog” means.

    • How do we mentally represent categorical knowledge?

    Organization of categories
    Organization of categories

    • Members of categories are organized in relation to some focal members. (prototype)

    • Focal members play the role of a “reference point.”

    • The boundaries of categories may be fuzzy, but people know pretty well which items are “good/bad” members of a category.

      • Penguin vs. robin, chair vs. rug,

    Measuring goodness of category members
    Measuring “goodness” of category members

    • Rosch et al. (1975)

    • Experiments:

    • Subjects were given a list containing the names of category members.

    • Subjects rated (using a 1-10 scale) the goodness of membership.

      • E.g., given “pistol”, subjects rated how good a pistol is as a member of the category “weapons.”

    • Furniture (chair, lamp, rug, dresser, desk, stove, table, stool, television, fan, bed, television, counter)

    • Fruit (apple, grapefruit, watermelon, banana, cherries, boysenberry, pear, strawberries, lemon, orange, pineapple, nut)

    • Vehicle (car, airplane, sled, bus, bicycle, wheelchair, truck, boat, tractor, ambulance, trolley, wagon).

    • Weapon (pistol, arrow, slingshot, sword, tomahawk, whip, knife, cannon, fist, rifle, club, bow)

    • Vegetable (peas, celery, mushrooms, corn, turnips, potatoes, carrots, tomatoes, green onions, green beans, artichoke, pumpkin)….

    • Other categories, bird, sport, toy, clothing.


    • Correlations: 0.95 or up (=1 is perfect correlation)

    • People agree very much which items are good/bad examples of a particular category.

    • Categories have “good” examples and “bad” examples.

    • The boundaries of categories are graded, and may be arranged probabilistically with “goodness” of membership.

  • What determine “goodness”? Or what makes a particular item a good example of a category?

  • Typicality and feature distribution
    Typicality and feature distribution

    • What makes an item a typical member of a category.

    • How do we perceive a particular item a typical member of a given category?

    Family resemblance rosch mervis 1975
    Family resemblance Rosch & Mervis (1975)

    • Distribution of attributes (features)

      • The most typical item in a category has the most features in common with other members of a category,

      • and the fewest features in common with the member of contrasting categories.

    • These items are ideal examples and may be referred to as “prototype.”



    Who is he she


    Who is he/she?









    • Morphed images of two different human faces

      ( Angelina Jolie – Brad Pitt by Na Yung Yu)

    Vertical structure of categories
    Vertical structure of categories

    • Why “dog” rather than “animal”?

    • Categories have a vertical structure.

    • Not all levels of categories are created equal.

      • One intermediate level of categories, which is called, basic level categories, plays a crucial role in our perceptual and cognitive operations

    Rosch et al 1978
    Rosch et al. (1978)

    • Basic (intermediate) level categories

      • Most efficient in identification

      • Evokes specific visual representations

      • People use this level exclusively for naming

      • Kids tend to learn these names earlier than other levels of categories

    Exp 1
    Exp. 1

    • Speed of classification

    • Shown a category name (animal -upper level, dog-intermediate level, or German shepherd low level) followed by a picture.

    • Subjects responded whether the category name matched with the picture (pressing a either yes or no key)



    Polar bear

    Results :

    Basic level items are the easiest to classify

    Basic level categories and representation
    Basic level categories and representation

    • Basic level categories evoke specific visual representations.

      • Given “furniture”, what kind of representation do you have in your mind?

      • How about “desk”?

    • Basic level category names evokes a specific pictorial representation

    Rosh et al 1978
    Rosh et al. (1978)

    • Object matching task and priming

    • Object matching task

      • Two pictures were shown on a screen briefly side by side.

      • Subjects’ task was to indicate whether or not the two pictures depicted identical objects

    2 conditions
    2 conditions

    • Primed trials

      • 2 seconds before the presentation of picture pairs, the category name of one of the pair was presented.

    • Non primed trials

      • No names were given prior to the trials.

    • Dependent measure

      • Accuracy and response time

    Procedure primed condition
    Procedure (primed condition)

    Animal / cat / Persian cat

    Depending on trials, upper (animal), basic (intermediate), or low level (Persian cat) category names appeared.


    • 15 subjects  primed with upper level names (animal)

    • 15 subjects  primed with basic level names (dog)

    • 15 subjects  low level names (German shepherd)

    • All the subjects were also given non-primed trials.


    RT for “Same”

    Priming conditions



    Basic level name (cat)

    Subordinate (kitten)















    • Given the name of a basic level category, people form a specific pictorial representation.

    Categories concept

    • Categories have a structure.

      • Horizontal structure

        • Distinction between dogs vs. Cats.

        • Prototype, family resemblance

          • The most typical item in a category has the most features in common with other members of a category,

          • and the fewest features in common with the member of contrasting categories.

      • Vertical structure

        • (Animal, mammal, dog, German Shepherd)

        • The mid-level categories that we used for naming are called “basic level” categories.

        • Basic level categories have cognitive and perceptual significance.