Concepts and Categories Flashcards
What are natural categories
- fuzzy sets (ill-defined boundaries)
- internal structure (variation in typicality, prototype)
- family resemblance (each member has at least one attribute in common with other members, but they won’t all share the exact same attributes)
they have a correlational structure (dimensions are not completly independent)
What is a category?
A category = a class of stimuli that are treated in an equivalent manner
Artificial categories:
feature dimensions can be combined arbitrarily
this compares to natural categories which have features that have correlational structures (you can’t just combine any feature values, if it has one dimension, its more likely to have a certain other dimension, etc)
Typicality:
some members of the category are good exemplars, some aren’t
different to artificial categories where each would be just as typical to that cateogry as the next member
family resemblance
how many features they share with other exemplars
- each feature is given a greater weight if its shared with other members
prototype = member of a category with the highest family resemblance scores
Internal structure of natural categories
- typicality gradient: some members of a category are better exemplar (more typical) than other members
- family resemblance: better exemplars share more attributes in common with other exemplars
Different levels of categories
Superordinate: very general category
Basic level: slightly more specific
Subordinate: very detailed
Basic level categories
Best balance between distinctiveness and informativeness
Distinctive: level at which there are many attributes common to members within the category, and few attributes in common with memebrs of other categories
Informative: communication is effective, learned first by children, expressed economically
Experts and the ‘subordinate shift’
Experts prefer subordinate names
Humans are all experts at ‘faces’ –> subordinate shift = faces are matched faster to subordinate level name than the basic level name
can also occur for objects (towers)
Downward shift = the idea that subordinate lables are quicker than basic level categories for things that we are familar with
