[Human Memory] 10.Knowledge

1. [Human Memory]10.Knowledge LEE JI HOON 2008.10.8

2. Question • 1. How do we access the information in generic memory? • 2. How to add up your knowledge?

3. What is knowledge? • Knowledge is what you know. • Generic memory • Everyday, ordinary knowledge • Includes other than purely semantic information • In this chapter, we use generic than semantic memory

4. Propositions and Concepts • Concept • A mental representation of something • Singing, Canary, Justice • Propositions • A relationship between two concepts that has a truth value • A canary can sing, A canary is a bird.

5. Collins and Quillian’s Hierarchical Model

6. Collins and Quillian’s Hierarchical Model • Three assumption • Retrieving a property and traversing the hierarchy take time. • The times are additive whenever on step is dependent on the completion of another • The time to retrieve a property is independent of the level of the hierarchy

7. Collins and Quillian’s Hierarchical Model

8. Collins and Quillian’s Hierarchical Model • Problems • No clear way of explaining performance on the false sentences. • The Contradiction hypothesis: search stops when a contradiction is reached • Unsuccessful Search hypothesis: search stops after a certain criterion is reached • Search and Destroy hypothesis: search continues until all possible connections are evaluated • None of these gave a good account of performance.

9. Collins and Quillian’s Hierarchical Model • Problems • There are often multiple representations and that structures may not be perfectly hierarchical.

10. The Feature Overlap Model • Defining feature • Essential for defining a concept • Characteristic feature • Usually, but not necessarily, true of a concept.

11. The Feature Overlap Model • X, overall similarity • C0, lower value • C1, upper value

12. Hierarchical vs Feature overlap • More quickly “A robin is a bird” than “A robin is an animal” • There are two levels of hierarchy to travel(hierarchical) • There are more feature overlap b/w robins and bird • More quickly “A canary can sing” than “A canary can fly” • Explained by the ordering of features • The most defining features are listed first

13. The Feature Overlap Model • Advantages • It can handle false responses • Which occur when the feature overlap b/w two concepts is very small • It can handle different kinds of false responses. • “Magnesium is an animal” is false than the proposition “A tree is an animal” • Problems • distinction between characteristic and defining features • Different production frequency • Butterfly -> insect is often mentioned, insect -> butterfly is rarely mentioned.

14. Collins and Loftus’s Spreading Activation Model • Revision of the basic hierarchical model • Activation spreads from one or two concepts to all related concepts. • 1. Some concepts can be represented multiple times. • 2. has links between concepts that have differential travel time. • 3. Explicitly allows activation to spread from both category and exemplar nodes.

15. Collins and Loftus’s Spreading Activation Model • Assumption • 1. When a concept is processed, activation spreads out along all paths; the strength of the activation decreases as the number of paths increases. • 2. Only on concept can be processed at a time, but once processed, activation can spread in parallel. • 3. Activation decreases over time and/or activity. • 5. The more properties two concepts have in common, the more links there are between the concepts. • 8. Decision process requires enough evidence to exceed a positive or negative criterion. • Other assumptions but not mentioned in text.

16. Collins and Loftus’s Spreading Activation Model

17. Collins and Loftus’s Spreading Activation Model • This theory is hard to disprove because it is difficult to predict and test • It is best viewed as a framework than a precise testable model. • This model quickly became a dominate explanation for theories of • Generic memory • Word production, word perception • Spreading activation model explain association priming

18. Conclusion • It is not yet clear exactly how generic memory is organized. • There is a limit on the amount of knowledge that a person can store and retrieve. • The data that we do have suggest that the more you know about something, the easier it is to acquire new related information.