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
