Concepts, categories and knowledge representation

what is a category?

a set of objects that can be treated as equivalent in some way

what is a concept?

a mental representation of a category

why do we need concept and category?

• to prevent information overload

• to make predictions

what is a problem with concepts and categories?

overgeneralisation and stereotyping

what is the definitional approach?

• classical view

• concepts are mentally represented as definitions

• membership is all or nothing

• all members of a category are equally good examples of it

what is typicality?

• the extent to which an object is representative of a category

• central= typical

• peripheral= atypical

what is the prototype approach?

• an ideal example that best represents a category

• summary representation of the category’s typical features leanred thhrouogh experience with category members

• probably does not correspond to any individual member

• graded membership- objects close to the prototype are better members of the category than objects further away from the prototype

Basic level of categorisation: Rosch et al

• superordinate

• basic

• subordinate

• SLIDE 21

Strengths of prototype approach:

• has been usefully applied to a range of conceptual tasks

• has led to fruitful theoretical ideas such as typicality, family resemblance and basic level concepts

what is a limitation of the prototype approach?

does not readily repreesent variability within a categorty

what is the exemplar approach?

• concepts are represented by stored examples alone

• no prototype is assumed

• readily represents variability in a category

Probabilistic appraoches:

• individuals can form prototype and exemplar representations simultaneously

• different cognitive mechanisms underlie prototype- and exemplar- based categorisation

• prototype representatioins= parietal areas

• exemplar representations= memory related areas

Theory/knowledge based approaches:

•