Ch. 8: Categories and concepts

1. Ch. 8: Categories and concepts

2. Concept and Knowledge • Topic: • How do we store and manipulate a concept in the brain?

3. Concepts, beliefs and behavior

4. 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

5. Psychiatric disorders • Anxiety disorder • Is created by an lingering belief on something threatening happens • Maniac depression • Disbelief on one’s ability, fate, etc.

6. 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

7. Stereotype • Ethnic conflicts

8. Concept and memory? • Are they two different things?

9. What is the structure of “concept”? This is the today’s topic.

10. Demonstration: • Tell me what you see as accurately as possible.

13. 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”?

14. What is “concept”? • I don’t know • But maybe concept we have is related to the way we categorize things

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

16. 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,

17. Nazi!! Fascists!! Terrorists, racists, sexists, pacifists, philanthropists, sophists, aristocrats, workers, bankers, lawyers, accountants, teachers, students, disciples, masters, gurus, beggars, bigots, • Party animals, beasts!!, dogs!!, • CEO, CFO, CIO, UFO, evp, vip, • IC (Indian Chief)

18. Ad hoc categories • 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

19. Circles, triangles, squares, dots, lines, rectangles, plane, • 1, 2, 3, 4, 100, 120, • A, B, C, D,…..

20. The format of representing a category

21. 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?

22. Which woman looks more attractive/friendly/pleasant/capable?

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

25. 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)

26. 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?

27. Alternative view

28. 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.

29. 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.

30. Birds: which one looks more like “bird”?

31. Which desk is the best example of “desk”?

32. 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

33. Fruit vs. Vegetable • Onion • Carrot • Pepper • Potato • Jalapeno • Cucumber • Bitter Melon • Spinach • Garlic • Ginger • Broccoli • Plantain • Lettuce • Cabbage • Pumpkin Banana Apple Melon Grapes Lemon Avocado Orange Grape fruit Kiwi Papaya Mango Lime Tomato

34. Example: • 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

35. 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?

36. 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,

37. 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.”

38. 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.

39. Results: • 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?

40. 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?

41. 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.”

42. Which woman looks more attractive/friendly/pleasant/capable?

43. Which woman looks more attractive/friendly/pleasant/capable?

44. + =

45. 12 Who is he/she?

46. 1 4 6 9 12 15 19 20 • Morphed images of two different human faces ( Angelina Jolie – Brad Pitt by Na Yung Yu)

47. By Na Yung Yu

48. By me

49. Just averaging the two faces