Semantic memory and the meaning of words

What is semantic memory defined as?

Word meanings linked to concepts and world knowledge

What are concepts described as being made of?

A collection of features

What are some types of features that make up a concept (e.g., for the word "dog")?

Sound (woof), feel (furry, warm), smell (wet dog), visual form (shape, colour, movement), and encyclopaedic knowledge (Can bite, Eats dog food, “Man’s best friend”)

What are two cognitive theories mentioned regarding how conceptual representations are organized?

Hierarchically structured models and Prototype models

What model suggests that concepts have a graded internal structure based on how typical a member is compared to the category prototype?

Prototype models

What theory proposes that concepts are grounded in bodily actions and perception (sensory-motor features)?

Embodied concepts

According to Embodied Concepts, what does processing a word like "JUG" activate?

Perceptual simulations and the actions it affords (drinking, grabbing, pouring), activating planning/execution structures

What models suggest that concepts in the brain are represented as distributed networks organized around sensory-motor functions?

Distributed models of semantic memory

According to distributed models, where is semantic knowledge or the representation of categories like "tools" vs. "animals" located in the brain?

It's in distributed networks of features, and there is no single meaning centre

What type of impairment involves difficulty understanding and naming items belonging to certain categories?

Category specific impairments

What is an example of a category specific impairment patient, who had more difficulty with living things than non-living things?

Patient JRB

Living things tend to be primarily known for what kind of properties?

Their sensory-perceptual properties (e.g., shape)

on-living things tend to have more emphasis on what kind of properties?

Their functional properties (actions and uses)

Category specific impairments might be explained by selective damage to either category knowledge (hierarchical models) or what type of features (distributed models)?

Selective damage of sensory-features or functional features

What progressive, degenerative brain disease particularly affects the anterior temporal regions?

Semantic dementia

In semantic dementia, which hemisphere typically shows greater degeneration?

The left anterior temporal region

Is the semantic deficit in semantic dementia specific to one sensory modality (like vision or hearing)?

No, it appears multi-modal

What core abilities are impaired in semantic dementia, regardless of how the information is presented (e.g., picture, spoken word, written word)?

Recognition and understanding of words and objects

What cognitive abilities are relatively preserved in semantic dementia compared to semantic knowledge?

Grammar (syntax), articulation (pronunciation), and episodic memory for events

In semantic dementia, what happens to the distinctive features of objects (e.g., when patients copy drawings from memory)?

They tend to be lost first, and drawings become more generic

Besides feature distinctiveness, what two other factors influence whether meanings are retained or lost in semantic dementia?

Familiarity/frequency and age of acquisition

According to prototype theories, what concept property explains why semantic dementia patients might confuse an emu or overgeneralize a butterfly as a bird?

Typicality of concepts

What model explains semantic dementia by proposing a modality-independent region where different features of meaning are integrated?

The Hub-and-Spoke model

In the Hub-and-Spoke model, what brain area is proposed as the central "hub" for integrating features of meaning?

The anterior temporal lobe

The Hub-and-Spoke model accounts for the distributed and convergent nature of conceptual knowledge but doesn't fully explain what two processes?

Processes involved in semantic decisions and context-dependent language use

What is a key aspect of semantic processing when understanding words in context (like "piano" in different sentences)?

Selecting which semantic features are relevant to the task or context

When performing meaning-related tasks that require a specific answer, does the brain activate all semantic associations?

No, it requires a selection process to produce a winning response