[Human Memory] 10.Knowledge

LEE JI HOON2008.10.8

Question1. 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 memoryEveryday, ordinary knowledgeIncludes other than purely semantic informationIn this chapter, we use generic than semantic memory

Propositions and ConceptsConcept

A mental representation of something Singing, Canary, Justice

PropositionsA relationship between two concepts

that has a truth value A canary can sing, A canary is a bird.

Collins and Quillian’s Hierarchical Model

Three assumptionRetrieving a property and traversing the hierarchy take

time.The times are additive whenever on step is dependent

on the completion of anotherThe 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.① The Contradiction hypothesis: search stops when a contradiction

is reached② Unsuccessful Search hypothesis: search stops after a certain

criterion is reached③ 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.

Collins and Quillian’s Hierarchical Model

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 overlapMore 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

AdvantagesIt 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 featuresDifferent production frequency

Butterfly -> insect is often mentioned, insect -> butterfly is rarely mentioned.

The Feature Overlap Model

Collins and Loftus’s Spreading Activation ModelRevision of the basic hierarchical modelActivation 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.

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 ofGeneric memoryWord production, word perception

Spreading activation model explain association priming

Collins and Loftus’s Spreading Activation Model

ConclusionIt 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.