psyc325 test 3 review

psyc325 test 3 review - The Nature of Categories necessary...

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The Nature of Categories - necessary and sufficient conditions (classical view) The classical view of categories goes back as far as Aristotle Categories are defined by a set of necessary and sufficient conditions. e.g., BACHELOR = an unmarried adult male. Each feature is necessary , and together they are sufficient to define membership of the category. - defining properties All members of the category must have the relevant properties. They are defining properties. These are artificial categories But natural categories (e.g., tool, chair, clothing) are not like this. - artificial vs. natural categories What are the defining properties of a game? There is no single property that all games possess. Ie shoe. Natural categories are everyday items as opposed to “large green triangle” Natural categories are fuzzy, with no clear-cut boundaries Family resemblance- the notion that members of a category resemble each other. In general, family resemblance relies on some number of features shared by any group of category members, even though these features may not be shared by all members of the category. Therefore, the basis for family resemblance may shift from one subset of the category to another. - no definining features, just features that are common Rosch and Mervis (1975) obtained ratings of “goodness of membership” peas and carrots are typical members of the category “vegetable” but rice and pumpkin are atypical examples. These ratings predict verification times (e.g., A carrot is a vegetable is verified faster than A pumpkin is a vegetable). Also, the more features a member shares with the other members, the more typical it is Rosch et al (1976): hierarchical organization of categories Three levels: superordinate categories (e.g., animal ), basic-level categories (e.g., dog ), and subordinate categories (e.g., poodle ). superordinate level- animal basic level- dog subordinate level- poodle
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All members of a category must have ___ relevant ___ properties (they are definining properties) According to Rosch’s theory of concepts, membership in a category is not all-or-nothing, but is _ graded _____ in typicality Prototypes The concept of prototypes For every category, there is a central member, the most typical member, and this is called the prototype. Rosch suggested that category membership was decided by comparing the properties with the properties of the prototype The greater the similarity, the faster the response. Prototypes result from averaging of properties at basic-level categories This explains the typicality effect. - the typicality effect- you are faster to categorize things that are more typical than atypical - evidence: sentence verification- A penguin is a bird ” takes longer to verify than “ A robin is a bird production- items close to prototype are listed earlier in a production task picture identification- items closer to the prototype are identified as members
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This note was uploaded on 04/08/2008 for the course PSYC 325 taught by Professor Forster during the Fall '07 term at Arizona.

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psyc325 test 3 review - The Nature of Categories necessary...

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