Thought: Knowledge Flashcards
What are the differences between episodic and semantic memory?
Episodic:
- reference to one self
- organised temporarily
- events recalled “consciously”
- Susceptible to forgetting
- Context dependent
What is challenging about studying episodic and semantic memories?
- there is a lot of interdependence between the two systems making distinctions unclear
What evidence is there supporting the distinction between semantic and episodic memory?
Semantic Dementia vs Alzheimers
What is the neuro-pathology of semantic dementia?
- non-alzheimer type degenerative pathology
- of the polar + inferolateral temporal cortex
- relative sparing of hippocampus in early stage
What are the symptoms of semantic dementia?
- progressive, selective deterioration in semantic memory
- reasonable preserved episodic memory
- *Where as Alz = episodic memory degradation
What did Graham et al in 2002 find when they compared SD and Alz?
Poor object naming in SD but not AD
- supporting distinction of Semantic and episodic memeory
In what ways does knowledge inform many aspects of language processing?
- language = more than just stored words/ grammar rules
- When reading + listening, we use knowledge to make inferences = underlies language comprehension
What are the different models proposed to explain the structure of Semantic Memory/ knowledge?
- Feature comparison Model: Smith et al, 1974
- Prototype Models: Rosch, 1973
- Exemplar Models
- Network Models
Describe the Feature Comparison Model by Smith et al, 1974.
- concepts (mental representations of objects/ categories) are stored as lists of defining or characteristic features
EG: Scientific verification task - typicality effect
What is the scientific verification task?
- Look at reaction time to verify a sentence
1. Is carrot a veg?
2. Is an artichoke a veg? - 1 = quicker response as a carrot has more characteristic features = Typicality effect
What is the typicality effect?
When a particular object is more recognisable than others due to it having more characteristic features
What is the limitation of the Feature Comparison Model?
- few concepts can be reduced to list defining characteristics: Game…. :\
- features are not independent of other info
eg: objects with leaves are less likely to have legs than objects than have fur
Describe the Prototype Model by Rosch, 1973
- Category membership is not clear cut INSTEAD…
- prototype models define the “centre” (avg) of a category VS its boundaries
- Prototypiclity effect
What is the prototypicality effect?
the avg description making it easier to identify concept
EG: Defining characteristics of “Bachelor” = unmarried man
- single 32 y/o man vs 9 y/o boy
= faster confirmation of single 32 y/o man as a bachelor
What is good about the prototypically models vs models that use categories?
- categories have a graded structures
= some are more representative (prototypical) than others
What are the key claims of the Prototype models?
- Prototypes differ from non-prototypes
2. Objects are categorised at 3 different levels
What does “prototype differs from non-prototypes”, one of the key claims of the Prototype model, mean?
- The examples of a category most often generated are also those rated as most prototypical; Mervis et al, 1976
- Semantic priming: we are faster to decide if “apple” is a word if it is presented by the unconsciously present word “fruit”
- where the priming effect is greater for prototypes
- prototypes share most features with other category members
What are the 3 different levels objects are categorised into?
- Superordinate
- Furniture, Animal - Basic
- Chair, Dog - Subordinate
- Armchair, Alsatian
Why does the basic level of categorisation have special status?
- used to name objects
- shows the largest semantic priming effects
- distorts memory
What are the benefits of the prototypical model?
- Can explain a lot of empirical findings
- allows “loose” concepts to be created
What are the limitations of the prototypical model?
- prototypes can change with context
- prototypes “lose” info
- Experts have different prototypes
What is an alternative view to protoypes?
use exemplar models
What is similar between exemplar and prototype models?
- both models involve comparisons between external reality + an internally generated “standard”
Describe the Exemplar Model
specific examples VS ‘avg’ prototypes drive the typicality effect
- easier to find specific memories of common objects compared to uncommon ones
