Prototype theory Flashcards
What is categorisation?
Seeing an entity as belonging to a larger set – a member of a group
What are the commonalities between the members of each category?
Recognition and Differentiation
What theory has been challenged and why?
- Aristotle’s: Categorialism
- Experts disagree on many of its most important and fundamental aspects - they are philosophically inaccurate.
What aspects make up the classical theory of categorisation?
- They have a definitional structure
- They were only challenged in the mid 1970s
- We can write a set of criteria for all categories which their
members will fulfil
What are categories defined by?
Categories are defined by necessary and sufficient criteria
- Necessary – each criteria is required individually
- Sufficient – only all of the criteria will collectively define the category
Aspects of the criteria (classical view of categorisation)
- The criteria are binary (either +X or -X)
- Something either belongs to the category or not
- Every instance of a category represents the category equally well
The problems with the classical model
The classical model sometimes has difficulties in finding a common set of definitional criteria.
-CAT:
[+mammal;+four-legged;+furry;+long-tailed;+pointy-eared] :
A three-legged cat?
A Sphynx cat?
A cat that has got in a fight and no longer has pointy ears?
Surely they are all still members of the category CAT – so the criteria cannot be seen as definitional.
What’s the problem of fuzziness ?
The definitional structure entails that categories have definitive boundaries
- For a category like Odd Number this seems fine – a number’s either odd or even
- But, what about a category like Furniture? Entities like table or chair are clearly in the category Carpet? Beanbag?
Theorists that argue against the ‘classical theory’ ?
Rosch & Mervis, 1975: that some items were deemed more typical of a category than others.
Who came up with the prototype theory?
Eleanor Rosch (1970)
What is the 2 main aspects of the prototype theory ?
- Principle of cognitive economy: gain as much information possible about the world whilst minimising cognitive effort.
- Principle of perceived world structure: the world around us has a correlational structure. Wings correlate with the ability to fly, rather than fur or ability to go under water.
What is the level of inclusiveness? (part of the prototype theory)
- Superordinate: Musical instrument
- Basic level: Guitar, Piano
- Subordinate: Folk guitar, classical guitar, grand piano
What test was given out to determine how representative an entity is in a category?
Subjects were given a list of members of a category, rating them on how representative they were.
From the results of the test, what conclusions are drawn?
- The most representative entity of a category is called the Prototype
- The less prototypical entities possess ever fewer relevant attributes
Issues with Prototype theory – Laurence and Margolis 1999 ?
- They propose that many concepts lack prototypes and they are not associated with typicality judgments.
- This reveals the problem that many complex concepts lack prototype structure and prototypical properties
What theorists said there was an issue with the prototype theory?
Laurence and Margolis 1999
What is the Idealised Cognitive Model ?
- ICMs guide cognitive processes like categorisation.
- Idealised because they abstract across ranges of experience rather than just representing individual experiences which have happened to the speaker
- Stable mental representations representing theories about the world
- Related to schema theory and the notion of frames
Aspects of ICMs (related to the idealised cognitive model)
- We construct a model based on pre-existing ICMs.
- Those ICMs might be: things with sentimental value; things with monetary value; etc.
The pope and ICMs:
Prototype theory would still say that the Pope can fall into the category BACHELOR.
- Lakoff: The Pope triggers an ICM of Catholic Church
- Knowledge of the Catholic Church blocks access to the ICM of Bachelor
- This explain the inappropriateness of calling the Pope a bachelor
What theorist constructs the Idealised Cognitive Model theory?
Lakoff (1987)
Summary of categorisation and prototypes:
- The classical view of concepts organising them on the basis of necessary and sufficient criteria
- There are many issues with this model: criteria cannot be found; exceptions can be found, etc.
- Prototype theory offers an alternative - Categories are organised around central exemplars and other members have a family resemblance
- ICMs can also be introduced as a means of resolving any issues with prototype theory
