Organization of Semantic Memory The study of Collins & Quillian (1969):Collins & Quillian (1969): The authors were interested in the organization of semantic memory. They developed a hierarchic network model that allows to represent concepts in memory. semantic memoryconcepts It is based on the assumption that categories consist of defining features.categoriesdefining features © POSbase 2003Contributor

Organization of Semantic Memory © POSbase 2003 has skin moves eats breathes Animal Bird Has wings can fly has feathers Fish Has fins can swim has gills Canary Can sing is yellow Ostrich Hierarchy: It is a hierachical network modell of semantic memory. Has long, thin legs can‘t fly is tall

Organization of Semantic Memory © POSbase 2003 has skin moves eats breathes Animal Bird Has wings can fly has feathers Fish Has fins can swim has gills Canary Can sing is yellow Ostrich Cognitive economy: Features are attached at highest level, not at each concept. Has long, thin legs can‘t fly is tall

Organization of Semantic Memory © POSbase 2003 has skin moves eats breathes Animal Bird Has wings can fly has feathers Fish Has fins can swim has gills Canary Can sing is yellow Ostrich Features of a sub- ordinate concept are not features for all exemplars of super- ordinate concepts. exemplars Has long, thin legs can‘t fly is tall

Has long, thin legs can‘t fly is tall Organization of Semantic Memory © POSbase 2003 has skin moves eats breathes Animal Bird Has wings can fly has feathers Fish Has fins can swim has gills Canary Can sing is yellow Ostrich Exceptions to the rule are assigned to sub- ordinate concept.

Has long, thin legs can‘t fly is tall Ostrich Organization of Semantic Memory © POSbase 2003 has skin moves eats breathes Animal Bird Has wings can fly has feathers Fish Has fins can swim has gills Canary Can sing is yellow Reaction times in classification task: Does a feature belong to the category? Canary: can sing < can fly < has skin

Seconds Canary can sing Organization of Semantic Memory © POSbase 2003 Reaction times in classification task: Does a feature belong to the category? Canary: can sing < can fly < has skin Canary can fly Canary has skin

Organization of Semantic Memory The authors concluded that their hierarchic network model can well explain the findings on classification times. However, there have been findings that were inconsistent with a model that assumes defining features (Rips, Shoben, & Smith, 1974).defining features For example, a robin is rated to be more typical as bird than a canary. Some theorists proposed a prototype view as an alternative to the view that categories consist of defining features. © POSbase 2003