L6: Knowledge in Semantic Memory

Question 1

How is general knowledge represented?

Answer 1

Represented in semantic memory, which stores the meanings of the concepts we know

Question 2

What is a concept?

Answer 2

A mental representation representing a category of objects, where a category refers to a set of objects that belong together

Question 3

Are concepts fixed or flexible?

Answer 3

Concepts are flexible

Question 4

What happens when you lose your general knowledge?

Answer 4

Semantic Dementia (distinguished from Alzheimer’s Disease). Widespread and profound loss of memory for concepts and word meaning

Question 5

What are the 4 approaches to concept organisation?

Answer 5

1. Common feature approach
2. Prototype approach
3. Exemplar approach
4. Embodied cognition approach

Question 6

What is common feature approach?

Answer 6

Uses features that are necessary and sufficient for something to be an instance of a concept

Question 7

Problems with common feature approach

Answer 7

Category boundaries sometimes too fuzzy to be handled by defining attributes

Question 8

What is prototype approach?

Answer 8

All categories have a central description or prototype that stands for the whole category. An object is a member of a category if it shares many attributes with the prototype

Question 9

What is concept of typicality effect?

Answer 9

Not every member of a category is equally representative (ie. penguin is a bird)

Question 10

What is typicality effect?

Answer 10

In category verification, decisions are faster for more typical members.

Question 11

Problems with prototypes

Answer 11

• Family resemblance scores did not predict typicality scores for members of goal-derived category.
• Evidence that best examples may be shaped by ideal instances rather than an average.

Question 12

Exemplar approach

Answer 12

• No prototype or defining features
• Instead, there is a memory system storing large numbers of specific instances
• ie. for a ‘bird’ category, you have a store of all birds encountered in the past

Question 13

Exemplars and Typicality Effect

Answer 13

Easier to verify that mynahs are birds compared to penguins since you have many more stored instances of mynahs

Question 14

What is knowledge-based approach?

Answer 14

We are sensitive to the relationship between features
- Two features of an ax are sharp and dangerous
- An ax is dangerous because it is sharp

Question 15

Disembodied mind

Answer 15

Body is divisible. Mind is indivisible. The mind of a man is entirely different from the body.

Question 16

Embodied mind

Answer 16

Bodily experiences play a fundamental role in shaping thoughts, emotions and perceptions

Question 17

Evidence for embodied cognition

Answer 17

• Perceptual anticipation theory says that the mechanisms used for visual imagery are the same as the ones used for perception
• Visual imagery activates similar areas in visual cortex as those involved in perception
• Processing concepts (eg. lick, pick, kick) activate relevant parts of the motor system

Question 18

Cognitive representation of semantic categories

Answer 18

Categories are often organised into hierarchies: Superordinate - Basic - Subordinate ie. Animal - Dog - Chihuahua
- Basic-level categories (ie. chair) are most useful -> people most likely to rely on basic-level labels to name pictures

Question 19

How can we assess semantic relatedness?

Answer 19

1. Word-association task
2. Feature overlap
3. Distance rating task

Question 20

What are propositions

Answer 20

Concepts can be combined into propositions, which is a configuration of concepts resulting in a true/false statement. Verbal messages are translated into a series of propositions that are stored in memory. The meaning is captured, but the specific words and order of words is lost. Frequent and familiar sequences of propositions can become grouped in schemas.

Question 21

What is a schema?

Answer 21

A set of related propositions, which forms a packet of typical knowledge about the world, events or people

Question 22

Schemas and semantic memory

Answer 22

We use schemas to store and retrieve information from semantic memory

Question 23

Uses of schemas

Answer 23

• Allows us to form expectations and take appropriate actions in the world
• Prevents cognitive overload
• Helps fill in the gaps in what we read or hear
• Helps us when we perceive visual scenes