language - semantic dementia Flashcards
(52 cards)
Hierarchical Structured Models (Collins & Quinlan, 1969)
How are concepts organized?
Concepts are organized in a hierarchy.
General concepts are at the top (e.g., “animal”).
Specific concepts branch below (e.g., “dog,” “cat”).
What is the principle behind Cognitive Economy?
Shared features are stored at the highest level to avoid redundancy.
More specific concepts inherit features from general ones.
“Can fly” is a property of birds.
Instead of storing “can fly” for robin, sparrow, eagle, etc., it’s stored once at the bird level.
So when you access “robin,” the brain assumes it inherits “can fly” from “bird.”
This helps the brain save memory space and process information efficiently.
How is information retrieved in Hierarchical Models?
Start at the general concept and move down to specific ones.
Faster retrieval of information through inherited properties.
What do prototype models argue?
- concepts made of frequent/typical features of typical category members
- graded internal structure as a function of similarity to prototype (whales, penguins)
- can make new things you might encounter
How do prototype models explain categorization?
Prototype models focus on similarity to a prototype.
Categories are determined by how closely an item resembles the prototype.
Why is categorizing whales and penguins challenging in prototype models?
They differ significantly from typical mammals and birds.
They share features with fish, making their categorization more complex.
What problem does the hierarchical model have?
It can’t explain why verifying “A penguin is a bird” takes longer than other category verifications.
What evidence supports hierarchical models?
Evidence from category verification tasks.
Participants’ reaction times increased when moving up through more nodes in the hierarchy
Example 1: “A canary is an animal”
This requires moving up two nodes: from canary → bird → animal. More steps → longer reaction time.
Example 2: “A canary is a bird”
This only requires moving up one node: from canary → bird. Fewer steps → quicker reaction time.
When people observe an action what occurs in the brain, such a running?
They will also have the leg area of the brain in the motor strip activated even if them themselves aren’t performing the action
what happens when you see the word of a concept in the brain?
The motor regions associated with this concept will also be activated - if you see someone using scissors, hands may be activated.
How do imaging studies show brain activity during action observation and performance?
Similar brain regions are active for both observing and performing actions.
Activity depends on the body part involved (e.g., mouth, hand, foot).
How does language relate to motor brain activation?
Language, especially action verbs, can activate similar motor brain regions as performing actions.
Concepts are grounded in body actions and perception.
What happens when you hear or read the word “jug”?
It activates perceptual stimulation related to the shape, size, and action associated with the object.
Actions like drinking or pouring are triggered, activating motor planning areas.
How are motor features activated during language processing?
When processing language related to actions, motor features associated with doing the action are activated.
This involves internal mental simulation of actions, similar to how mirror neurons work.
What is the overlap in brain activity when performing actions or hearing action-related words?
There is an overlap between brain regions activated when you perform an action with a body part and when you hear a word related to that body part.
Is there a single meaning centre in the brain?
No, concepts are a distributed network organized around sensory-motor functions
how are concepts organised across the brain?
there are groups of words across the brain, organises by connection
What is embodied cognition theory?
The theory that our thoughts, knowledge, and understanding are shaped by our bodily experiences.
Mind and body are connected in how we process the world.
How does embodied cognition theory explain understanding concepts?
We understand concepts through our bodily experiences, not just abstract thinking.
Our brain activates motor and sensory areas related to physical actions when thinking about certain concepts.
What is a problem with embodied cognition theories?
Abstract concepts like “TRUTH” or “BELIEVE” don’t have clear physical actions or sensory-motor features tied to them.
It’s difficult to explain how we simulate or understand these abstract concepts through bodily experiences.
Who is JRB and what type of impairment does he have?
JRB is a patient with category-specific semantic impairment—difficulty recognizing living things but intact recognition of non-living things.
How do hierarchical models explain JRB’s impairment?
Hierarchical models suggest that semantic knowledge is organized in category trees.
JRB’s impairment reflects damage to the higher-level category node for living things, which disrupts access to all related concepts beneath it.
What are hierarchical models of semantic memory?
These models organize knowledge from general to specific, where broad categories (e.g., animal) lead down to specific items (e.g., dog). Damage to higher nodes affects all lower nodes.
What brain damage could explain JRB’s impairment?
Damage to the ventral stream of the visual cortex, affecting shape and perceptual representations.
Limited ability to access sensory features for living things.
