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
What are the benefits of the exemplar models?
- do not require abstraction
- preserves info about variability like could this be a pizza or a ruler?
How many inches = more likely to see a larger pizza vs ruler as found by Rips + Collins in 1993?
12”
What are the limitations of the Exemplar model?
- applies to complex more than simple categories
- infers that we store every single example of a category
What are the different Network models?
- Hierarchical Nets; Colins + Quillian, 1969
- Semantic Nets; Collins + Loftus, 1975
- Adaptive Control of Thought- Rational (ACT-R); Anderson, 1983, 2000
- Parallel Distributed Processing (PDP); McClelland + Rumelhart, 1986
Describe the network model: Hierarchical Nets by Colins + Quillian (1969)
- emphasise the relationship between concepts
- relate to feature comparison models since it looks at features + concepts
What are the key concepts of the Hierarchical Nets, Network model?
- concepts represented by nodes
- Nodes connected by links
- Semantic relatedness
EG: people faster to verify Canaries are yellow vs have feathers
What is a limitation of the Hierarchical Nets, Network Model?
- ppt are very fast to verify “peacocks have feathers” which doesn’t describe how these features are represented
What are the key concepts of the Semantic Nets Network Model by Collins + Loftus in 1975
- semantic distance
- spreading activation - if one is activated, the closest one would be activated
- link strength or weight (depicted by semantic length here)
What evidence are there supporting the semantic nets, Network Model for structure of semantic memory?
McNamara, 1992
- semantic priming greater for “closer” items
- which explains the false memory effect = DRM paradigm
What is the DRM paradigm?
Deese-Roediger-McDermott paradigm
- false memory
- being able to remember specific words, but they also remember another detail just due to semantic relatedness even though it isn’t an original word on the list
- RL context: EWT
Describe the ACT-R network model
Adaptive-control of thought- rational
- a theory of all cognition
- declarative memory is one small part
- more often links are activated the faster they become
- number of links that can be supported is limited by the strength of the concept
- assumes a finite amount of activation - if spread thinly, then decisions are slower and acquiring new connections is harder
- Fan effect
What is declarative memory?
- smallest unit of info that can be declared true or false
What is the Fan effect?
time to make true/ false decision increases with the number of items of info associated with the location and person
What are the key features of the Parallel Distributed Processing Network model by McClelland + Rumelhart in 1986
- “neuron” like nodes connected by links
- a concept represented by a pattern of activity distributed across many nodes
- links have different “weight” strength
- info processing proceeds in parallel – many patterns of spreading activation may occur at the same time
- PDP models allow for spontaneous generalisation and graceful degradation
What does graceful degradation mean?
- how when we start to age, tent to forget details of a concept where one link starts to decay slowly over time, just gracefully degrading
Other than just concepts, what do semantic memory store?
- Schemas
- Scripts
What are schemas?
generic info about situations/ general rules that are typically accurate
- research into this area fell out of fashion whilst behaviourism was dominant
- highlights the interplay between “top down” + “bottom-up” in for processing
What are scripts?
structured, ordered sequence of events
- can be a prototype
- an abstraction
What did Brewer + Treyens in 1981 find about schemas and retrieval?
Schemas can distort memory
- ppt asked what they say when they were in a waiting room for 35 min
= things that are expected to be there were recalled
- books
- not recall picnic hamper + wine bottle
