By the end of this lecture, you will learn: –How to see sound and hear colors –How to alter the perceptions of others –How to know what you don’t know The most ingenious of Aristotle’s conclusions is that metaphor is above all a tool of cognition - Umberto Eco, on Aristotle Knowledge Representation Representations are Graded Knowledge Acquisition

Knowledge Representation Units of knowledge allow intelligent behavior – they are an organizational unit of knowledge Categories

Knowledge Representation What are categories really? Categories are structured relationships between items. Structured on the basis of: –Shared features –Shared purpose –Shared context

Knowledge Representation Where are categories stored? Double dissociations of category neurons –Living things –Nonliving things

Knowledge Representation Where are categories stored? (cont.) Category specific neurons –Some neurons fire selectively to: Animals –Spiders –Seals –Horses Famous people –Jennifer Aniston –Halle Berry Landmarks –Tower of Pisa –Sydney Opera House Etc…

Knowledge Representation How are categories stored? Definitional Approach –“What makes a game?” It’s an activity most often practiced by children It’s engaged in for fun Has certain rules Involves multiple people It’s in some ways competitive

Knowledge Representation How are categories stored? (cont.) Similarity Approaches –Prototype Theory –But priming suggests it’s not just one prototype… First View pictures of Cujo Then you’re faster to recognize mean dogs as dogs than nice ones

Knowledge Representation How are categories stored? (cont.) Similarity Approaches –Exemplar Theory Instead of an “idealized” member, there are many examples which are actual items encountered in the past. Some research supports the idea that we store these specific cases, other research doesn’t

Knowledge Representation How are categories stored? (cont.) Definitely not definitional A little of both prototypes and exemplars –Each category has multiple prototypes, which are in some cases the actual items themselves –Prototypes are updated through experience –Large categories vs. small categories

Knowledge Representation Structures of structures of structures of… Superordinate, Basic, & Subordinate

Representations are Graded Graded Membership Typicality ratings of… Furniture: 1.Chair 2.Sofa 3.Chest 4.China closet 5.Drawers 6.Mirror 7.Wastebasket 8.Telephone Vehicles: 1.Automobile 2.Ambulance 3.Bicycle 4.Tractor 5.Canoe 6.Horse 7.Skis 8.Elevator Birds: 1.Robin 2.Sparrow 3.Hummingbird 4.Raven 5.Owl 6.Duck 7.Penguin 8.Bat

Representations are Graded Features of Typicality Typical category members … –Have high family resemblance –Can be verified as members more quickly –Are named first –Are more subject to priming

Representations are Graded Priming and Typicality Priming effects depend on similarity of primed category to target category –If you think humans are comparable to animals –If you think humans are really different + + = = MEN ARE REALLY FAST TURTLES MEN ARE AS SLOW AS TURTLES

Representations are Graded Typicality of Airplanes and September 11 th Other contributions to typicality: –Frequency of exposure “blah blah blah Airplane blah flight number blah blah” –Or Frequency of instantiation? “blah blah airplane as a weapon blah blah blah airplane explode blah blah”

Reasoning With Knowledge Inductive vs Deductive Inductive –From item to category Deductive –From category to item

Knowledge Acquisition How did you learn the things you know? There are some basic principles…but we still don’t know the whole story There is agreement that it has something to do with integrating and structuring information from multiple modalities, in a flexible way Maybe WM span… or maybe categories?

Knowledge Acquisition Thinking about what you know “loud colors” of the early 90s The “dark sounds” of The Cure The “sweet smells” of home The “sharp crack” of a whip

Knowledge Acquisition Do you actually know what you think you know? “Unskilled and Unaware of It” –The most incompetent people are also the most unaware of their incompetence

Video of “Dimensional Change Card Sort” At the Cognitive Development Center Yuko Munakata, Primary Investigator Knowledge Acquisition What does it mean to know?

Explore on your own…. Jobs –Cognitive Engineering –Knowledge Engineering –Knowledge Management Google search phrases –Concept Learning –Project Halo or Cyc –Expert Systems (Act-R)