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Chapter 7

Psychology 2135A/B Chapter Notes - Chapter 7: Basal Ganglia, Eleanor Rosch, Implicit Learning


Department
Psychology
Course Code
PSYCH 2135A/B
Professor
Robert Brown
Chapter
7

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Chapter 7 - Concepts and Categorization
- grouping of things into larger groups is categorization
- mental representation of a category is a concept
- doctors categorize illnesses to determine diagnosis
- Medin (1989) argues concepts and categories serve as building blocks for human thought and
behaviour
- Lamberts and Shanks (1997) argue how concept are mentally represented is a central concern
to cognitive psychology
- concept: mental representation of some object, event, or pattern that has stored much of the
knowledge typically thought relevant to the thing
- category: class of similar things that share one of two things:
- an essential core
- or some similarity in perceptual, biological, or functional properties
- Medin says categories are existing objectively in the world and concepts are mental
representations of categories
- Medin & Smith (1984) argue concepts help us establish order in knowledge base
- concepts allow us categorize, to treat new things in same way we treat familiar things that we
perceive to be in the same set (Neisser, 1987)
- categorization allows us to make predictions and act accordingly
- concepts play important role; reduces too much new information and allows easy language and
communication (Smith and Medin, 1981)
Theoretical Descriptions of the Nature of Concepts
The Classical View
- dates back to Aristotle to 1970s
- features: a component of an object, event, or representation
- classical view of concepts: all instances of a concept share fundamental features
- features represented are individually necessary and collectively sufficient
- assumes that concepts mentally represent lists of features
- assumes that membership in a category is clear-cut
- implies all members within a category are created equal
- Eleanor Rosch criticized view
- found that people judge different members of a category as varying in "goodness"
- people more likely to list typical than atypical instances of a concept
- people respond faster to typical examples
- highly typical instances often led to better priming in semantic priming studies
- McCloskey and Glucksberg (1978) found people do not have clear boundaries, especially for
atypical instances
- concluded that membership is graded and boundaries are fuzzy
- most people cannot generate lists of features that are individually necessary and collectively
sufficient to specify membership
The Prototype View
- prototype view of concepts: all concepts are organized around idealized mental
representations of examples

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- denies existence of necessary and sufficient feature lists, except for a limited number of
concepts like mathematical ones
- prototypes: abstract representation of an idealized member of a class of things
- prototypes include features that are characteristic
- no individual feature, except very trivial ones, need be present to count as member
- more characteristic features an instance has, more likely to be regarded as member
- family resemblance structure of concepts: Wittgenstein (1953); each member shares different
features with different members; few, if any, features shared by each member; more features a
member possesses, more typical it is
- Rosch and Mervis (1975) had people list features of individual items in categories and found
very few features true of all items for a category
- often thought of as mental summaries or averages of all instances
- concepts have one or more core representations but not rigid boundaries
- concepts exist at many different levels of a hierarchy; higher-level (superordinate), lower-level
(subordinate)
- Rosch and colleagues found another level, the basic level
- basic level of categorization: hypothesized type of concept thought to be at a
psychologically fundamental level of abstraction
- compromise between grouping similar objects and distinguishing among objects
- superordinate levels of categories: broader than basic level, including exemplars that can be
quite dissimilar from one another
- subordinate level of categories: thought to make fewer distinctions than basic level
- criticisms of prototype view:
- fails to capture people's knowledge about limits of conceptual boundaries
- Rosch and colleagues counter-argued that some constraints come from environment
itself, from the way world works; we just pick up information about world's regularities, not
impose arbitrary groupings
- typicality ratings depend to some extent on context; varies with way concept itself is
being thought about
- Armstrong, Gleitman, and Gleitman (1983) found that typicality ratings task is flawed,
at least for discovering underlying representation of concepts
Thee Exemplar View
- exemplar view of concepts: concept consists of mental representations of actual instances or
examples
- people categorize new instances by comparing them to representations of previously stored
instances, called exemplars
- no necessary and defining features to be stated
- explains difficulty in categorizing unclear, atypical instances
- typical instances thought to be more likely to be stored than less typical ones, or to be more
similar to stored exemplars, or both; therefore faster processing for typical
- Allen and Brooks (1991)
- trained people on fictional creatures and gave defining features for each
- people took longer to classify and made many more errors in categorizing negative
matches that others
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