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Memory

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  1. Memory Semantic Memory

  2. Outline • Models of Semantic Memory • Hierarchical Network Model • Spreading Activation Network Model • Schemas & Scripts

  3. Semantic Memory: Hierarchical Model • Collins & Quillian • Semantic Memory is organized as a network of • Units (nouns): shark, robin • Properties (verbs or adjs): is yellow • Pointers: specify relations between units

  4. Living Thing Breathes Animal Plant Feathers Bird Mammal Ostrich Barks Dog Bat Canary Yellow

  5. Hierarchical Network Model • Using semantic memory = searching through network for relevant information. • Assumptions: • Cognitive Economy • Searching the network takes time • More distance => more time • Advantages? Disadvantages?

  6. Hierarchical Network Models: Evidence • Reaction Time • Sentence verification task • A canary is yellow. • A canary breathes.

  7. Living Thing Breathes Animal Plant Feathers Bird Mammal Ostrich Barks Dog Bat Canary Yellow

  8. Hierarchical Network Models: Evidence • Problems • Typicality effects • An ostrich is a bird. • A canary is a bird.

  9. Living Thing Breathes Animal Plant Feathers Bird Mammal Ostrich Barks Dog Bat Canary Yellow

  10. Hierarchical Network Models:Problems • False sentences • A bat is a plant. • A bat is a bird.

  11. Living Thing Breathes Animal Plant Feathers Bird Mammal Ostrich Barks Dog Bat Canary Yellow

  12. Spreading Activation Networks • Collins & Loftus • Also involves nodes and links. • Links need not be hierarchical. • Activation spreads between nodes. • Further = weaker • Activation speeds processing • Allows for more flexible representations.

  13. Spreading Activation Networks: Evidence • Meyer & Schvaneveldt • Priming • Change in readiness to perform a task resulting from prior information about the task. • Facilitation (positive priming) • Inhibition (negative priming) • Lexical Decision Task • Stimulus is presented. • Task is to decide whether it’s a word. • Interested in time that decision takes.

  14. Lexical Decision Task NURSE

  15. Lexical Decision Task PLAME

  16. Lexical Decision Task NURSE <======RT=======> ”Yes” PLAME <================> ”No”

  17. Lexical Decision Task: Results

  18. Lexical Decision Task: Results

  19. Problems with Spreading Activation?

  20. Schemas • Large unit of representation that organizes relations among concepts, situations, events, and/or actions in memory. • Jane heard the jingling of the ice cream truck. She ran to get her piggy bank and started to shake it. Finally some money came out.

  21. Schemas • How old is Jane • Why did she get the money? • Did she turn her piggy bank upside down? • Did bills come out? • How big was the piggy bank? • Where was the piggy bank located?

  22. Scripts • Script: “A knowledge structure containing the sequence of events that usually occurs in a particular common situation.” • Going to the Dentist • Going to a Restaurant • Taking an Exam

  23. Schemas & Scripts: Implications • Integration: Info from specific events combined with general knowledge • Experience shapes scripts • Scripts guide recall • Advantages & Disadvantages • Implications for Episodic-Semantic distinction?