L3 - Categorisation Flashcards
What is semantic memory?
- Type of explicit memory
- Knowledge about things in the world and their inter-relationships: words & meaning, objects and places.
What kinds of memory is selective attention?
STM & Working
What are implicit/explicit memories?
- Implicit = lot harder to explain, usually skills e.g walking etc
- Explicit = memories we can consciously access and verbalise
How does inference play a part in memory?
- Knowledge is inferred from what we know about other related things
- Helps to make sense of world and make predictions
what are concepts for organising the world?
- When we experience things, we organise them too
- The instance belongs to a category
What is knowing?
- What category it belongs to
- What it is similar to/ belongs with
- We know lots about it without encountering it
- The meaning of a word = accessing its concept.
What is a semantic network?
- Way of organising knowledge
- Originally, info was organised hierarchically: ordinate concepts, sub-ordinate concepts.
- All will share some attributes to prevent duplication
What are the principles of the structure of the semantic network? (APE)
Economy - each sub inherits attributes from ordinate to prevent too much storage.
Accessibility - we should access info that is stored by searching through nodes of the network
Predictions - about specific instances can be made as every situation is a novel one even if similar to previously encountered ones.
Evidence for Defining-Attribute view
- Speed of response is measured
- When asked to list defining attributes, people start with ones on the same level as a ‘probe’ concept
- Speed depends on distance travelled in the network to find the evidence
- Could ask people to generate list about a category, people start with attributes on the same level before moving elsewhere
What are the problems with defining attributes?
- Some attributes are more salient (stand out)
- Might not be about distance, just salience
- Salience depends on context, and behaviour changes with this
- Categories can be flexible: e.g toy zebra vs real zebra
Problems with the semantic network
- Defining what makes a category is hard
- What are the defining attributes of this category?
e.g games must share qualities but be different to other things - Typicality: not all ex are equivalent even though they have the same attributes, some are more typical e.g pigeons vs eagles
- Typicality can change how long people take to make judgments e.g triangles
What is the exemplar view of categorisation?
- Categories are clusters of exemplars, things that co-occur together
- Explains typicality due to frequent interactions with them
Positives of clusters
- More fluid, focusing on diff dimensions to see diff categories
- No clear boundaries
- Correlations between features enables prediction
- Hierarchy = zooming in/out
What is Semantic Dementia?
- Progressive, selective loss of semantic knowledge in any modality
- Loss of word meaning: can speak but sounds foreign to them
- Can’t recognise objects
- Other cognitive abilities and aspects of language are preserved better
- Alz = episodic memory affected initially
What are everyday effects of semantic difficulties?
- Surgeon (DM) had to stop working as he could not remember the names of instruments or how to use them
- AM had difficulties in naming people & objects: poured orange juice over pasta etc
- JL presented similar things to AM, worried about beard hair and didn’t know what it was
- People lose subcategories first
