Theories of categorization

Question 1

probabilistic theories of categorizations and its criticism

Answer 1

failure of classical theory led to proposal that category representation may be probabilistic rather than deterministic

two approaches:
prototype theory
exemplar theory

both based on idea of similarity

criticism
– similarity is relative - require knowledge what features are being compared

similarity along which dimension
– how are they similar

similarity requires some assumptions that aren’t always met
similarity or typicality not alway a goof indication : lemon that is painted blue
our beliefs about essential properties strongly influence our judgement

Question 2

What does Prototype theory state? what are its criticism

Answer 2

categories = average of all members of categories
category membership made by comparing a new instance to a prototype
prototype does not need to exist in the real world
abstract
typicality and graded category explained by similarity to prototype

study: Posner dot experiment

criticism:
information about individual instances are not stored
– not the case in reality
doesn’t have a way to take into account the variance in a category
no info about the spread only the center

Question 3

What is the exemplar theory? criticisms?

Answer 3

• concepts are represented by all of the exemplars that have been experiences
  derive a prototype if needed but not automatic
  do exist in the real world
  typicality and graded membership explained by frequency

criticism?
no blending of the individual instances stored
trouble scouting for people’s ability to extract general properties

Question 4

which one is right?

Answer 4

use both under different circumstance 
prototypes - general knowledge 
exemplars - more detail 
every concept is a mic of both 
with more experience - use both