Lecture 9 (Ch.9 knowledge)

Question 1

What is knowledge?

Answer 1

o Memory for facts, understanding, other information…
o AKA: long-term, explicit, declarative, semantic memory
o Associated with concepts
o Mental representation of a class or individual

Question 2

What is conceptual Knowledge?

Answer 2

Ability to recognize objects and events

Make inferences about properties

Question 3

Categories

Answer 3

Pointers in knowledge 
Shorthand version of more general information about items 
Also helps to characterize differences 
 - Cases not previously encountered 
 - Distinguish special characteristics

Question 4

Definitional Approach

Answer 4

Using formal definition to determine membership

- Problems: doesn’t work for some categories

Question 5

Family resemblanc

Answer 5

similarities b/w members (we can do the same to categorize things)

Question 6

Prototype Approach

Answer 6

Prototype: Average or typical representation of something.
Characteristic features .
Average of members encountered
Idea of the “perfect” or ideal member (use for comparison)

Question 7

High vs. Low prototypicality

Answer 7

High: resembles prototype a lot
Low: doesn’t really resemble prototype

Question 8

Typicality effect

Answer 8

Higher prototypicality = faster naming

Question 9

Exemplar approach

Answer 9

Similar to prototype

• Represents category without defining it BUT
• Use of multiple examples (rather single prototype)
• Actual category members (not abstract averages)
• Comparison of new items with exemplars
• Explains typicality effect
• Takes into account atypical cases
• Easily deals with variable categories (ex: games)

Question 10

Do we use prototype or exemplars more?

Answer 10

Some evidence – likely use both
May depend on
- Category size?
•Prototypes better for larger categories
•Exemplars – smaller, more specific categories
- Initial vs. later learning?
•At first – prototypes –> exemplars (ex: is a dolphin a fish?)

Question 11

Hierarchical

Answer 11

Cetegories are hierarchical 
From superordinate (Global), basic, subordinate (specific)

Question 12

Semantic networks

Answer 12

Associations within categories.

Lower level items share features with higher level items

Question 13

General Model (Collins and Quillian)

Answer 13

The network consists of nodes that are connected by links. Each node represents a category or concept, and concepts are placed in the network so that related concepts are connected. In addition, a number of properties are indicated for each concept.

It is hierarchical

Cons: Doesn’t explain typicality effect

Question 14

Connectionists model

Answer 14

Approach to creating computer models for representing cognitive processes.
parallel distributed processing (PDP) models propose that concepts are represented by activity that is distributed across a network.

Can account for network changes (learning)
Adjusting weights at connections (synapses) –>Affects strength of next signal

Question 15

Steps in connectionist model

Answer 15

Step 1 – environment --> input 
Step 2 – input --> hidden 
•Various routes 
•Changeable connection strengths 
Step 3 – Hidden --> output

Question 16

How do we learn

Answer 16

o If provided with correct response

• Can correct errors
• “Error signals”
• “Back-Propagation”
• Adjust Strengths of Connections

Question 17

Properties of Connectionist Model

Answer 17

Learning: initially slow but generalized
Can use many different types of inputs
Concept is distributed across network
Overtime: can use various routes to arrive to the same output
Robust and resistant to change (graceful degradation)

Question 18

Embodied Approach

Answer 18

our knowledge of concepts is based on reactivation of
sensory and motor processes that occur when we interact with the object

Mirror Neurons*

Question 19

sensory-functional (S-F) hypothesis

Answer 19

the sensory-functional (S-F) hypothesis:t our ability to differentiate living things and artifacts depends on a
semantic memory system that distinguishes sensory attributes and a system that distinguishes function.

Question 20

semantic category approach

Answer 20

proposes that there are specific neural circuits in the brain for some specific categories

Question 21

Multiple factor approach

Answer 21

multiple-factor approach but this approach focuses not on brain areas or networks that are specialized for specific concepts but on searching for more factors that determine how concepts are divided up within a category.

Question 22

Semantic Dimensia

Answer 22

Progressive loss of semantic and conceptual knowledge - Both verbal/nonverbal

Bilateral Anterior Temporal Lobe degeneration

 Typically start with naming problems
 But in the presence of relatively spared episodic memory
 Progressively – more general problems w/verbal and nonverbal concepts
 Abstract vs. concrete

Question 23

What the approaches agree on

Answer 23

all of the approaches agree on is that information about

concepts is distributed across many structures in the brain