[Human Memory] 10.Knowledge LEE JI HOON 2008.10.8

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

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

Propositions and Concepts 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.

Collins and Quillian’s Hierarchical Model

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

Collins and Quillian’s Hierarchical Model

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.

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

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

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

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

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.

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.

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.

Collins and Loftus’s Spreading Activation Model

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

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.