semantic representations

Question 1

What is semantic memory?

Answer 1

Semantic memory represents our general knowledge of the world, including facts, meanings and objects. It plays a central role in cognition (langugae, memory and perception).

Question 2

What is the N400 component?

Answer 2

The N400 is a negative peak (occurring after 400ms after onset) which is elicited by a word’s appropriateness in a given context. It’s amplitude is greater when their are semantic anomalies or knowledge incongurencies.
It does not depend on presentation modality.

Question 3

How does spreading activity relate to the N400 response?

Answer 3

Concepts - organised in a network which are activated via spreading activity
Means when primed with a word - elicits a number of concepts to be activated
N400 modulated by semantic connection between expected and presented word - larger when unexpected

Question 4

What are the key features of models of semantic memory?

Answer 4

We have representations of concepts which are organised in a network.
Activation of one concept will activate associated concepts.
Spreading activation
Concepts are comprised of its constituent features (properties of or facts about a concept which are linked together by a network ).

Question 5

What are the key difference between models of semantic memory?

Answer 5

organisation - hierarchical vs non-hierarchical
feature format - amodal vs grounded
category specificity - innate or emergent?

Question 6

Distinguish between a ‘concept’ and a ‘feature’ of semantic memory using an example.

Answer 6

Concept = lion
Feature = lion is an animal, it is a carnivore, it has 4 legs

Question 7

Explain the difference between amodal and grounded representations of semantic memory.

Answer 7

Amodal (older) - abstract and not connected to sensory or motor information
independence of input and output modality because same semantic memory can be accessed by multiple kinds of sensory input

Grounded - solution to symbol grounding problem
representations/concepts not defined in terms of each other, but our experience and interactions with them in the world
Concept representations are distributed over distinct brain areas.

Question 8

Give an example of an amodal model and a grounded model of semantic memory.

Answer 8

Amodal - hierarchical organisation
Grounded - proposal that emotions are defined in terms of their bodily feelings

Question 9

What is the Chinese room problem, and what does it suggest about language understanding?

Answer 9

Searle’s Chinese Room problem - language understanding comes from the understanding of both syntax and its relative meanings

Question 10

Describe the research findings regarding language capabilities in non-human primates like Washoe and Koko.

Answer 10

Washoe (200 signs) and Koko (1k signs) learned to use manual signs, but their understanding was limited to associations rather than true language comprehension.

Question 11

Outline the 3 key studies regarding the language capabilities of primates.

Answer 11

Kanzi the chimp
learned how to use arbitrary written symbols to communicate and could select the symbols in response to human speech
Suggested that Kanzi could use these symbols flexibly and follow word order but this research was criticised because Kanzi’s utterances were mainly food requests that may have been learned through reward

Washoe
learned 200 signs - evidence of overgeneralisation

Koko
1,000 signs, which she was able to combine in complex ways

Question 12

Describe research into the infant N400 response.

Answer 12

9m/o infants elicited a larger N400 response to mismatches between an object and a preceding a label (primes object that should be seen next)
Used to track the understanding of certain semantics/meanings of words

Question 13

Explain the concept of category specificity in semantic knowledge.

Answer 13

Category specificity = activation of certain brain regions are specalised for retrieving info about specific categories’ features or attributes
Representations are widespread and overlapping on the brain.

Question 14

Outline what research has found about category specific activation for animals ans tools. How does this link to grounded theory?

Answer 14

Naming pictures, reading names, answering questions or thinking of animals and tools elicit category related activity in ventral occipito-temporal cortex
Reading/thinking of a concept - activates the visual (or relevant part) where info was connected to.

Question 15

How does the idea of category specificity support grounded models of semantic memory?

Answer 15

Category-related activations reflect the link between semantic information and its category specific features and attributes.Object representations are not limited to a specific area, but is widespread and overlapping.

Question 16

What evidence is there to support the idea of category specificity in semantic memory?

Answer 16

Category specific deficits - e.g case study Farah and Rabinowitz (2003) where Adam had a selective impairment of knowledge for living things

Question 17

Explain the argument for the idea that category specificity is an emergent property.

Answer 17

Different categories rely on different types of knowledge/characteristics
Sensory-functional distinction: 2 categories - one for animals (sensory characteristics more important) and one for tools/man-made objects (functional characteristics are more important)
Categories emerge/refined based on our experiences

Question 18

Outline the theory and evidence which supports the idea that category specificity is innate.

Answer 18

Argues Some categories are hardwired - animals, plants, conspecifics (other humans), tools
Evidence:
Prenatal preference for face configurations
Newborns prefer biological motion
Congenital blindness - visual stim elicit category-specific activity in VTC even in people who were blind since birth

Question 19

Discuss the Farah and Rabinowitz (2003) case study and what it suggests about category specificity.

Answer 19

Adam was born with no representation of of living things but has normal representation of inanimate objects.
As he was born this way, experience could not have contributed to this distinction suggesting we have an innate readiness to distinguish living and non living things.

Question 20

What is the symbol grounding problem and how does it challenge amodal models of semantic memory?

Answer 20

The symbol grounding problem suggests that the understanding of new concepts relies on prior understanding of other concepts, which means abstract representations alone would not allow us to gain further understanding of the world.

Question 21

What is the neural basis of semantic memory?

Answer 21

activation in the temporal lobes