6 semantic memory (LTM)

• Learning objectives


  1. Concepts & their importance

  2. Theoretical approaches to concept organisation (A) common feature, (B) prototype, (C) exemplar, (D) embodied cognition

  3. Organisation of concepts, how are concepts organised

  4. Schemas and stereotypes
• Semantic memory


  Long-term memory that stores meanings of concepts
• Concept


  Mental representation that represents a category of objects with associated features
• Category


  Set of objects that belong together
• Importance of concepts


  • Efficient way to represent the world
  • Correctly identify and assign categories to make important decisions and accurate predictions about objects in the world
• Caveats to category membership
• Semantic dementia
• Theories of concept organisation

  • Common feature approach
  • Prototype approach
  • Exemplar approach
  • Embodied cognition approach
• Common feature approach


  • Defining attributes that are necessary and sufficient to make up a concept
• Problems with the Common feature approach
• Prototype approach


  • Central, average description/prototype that stands for the whole category
• Limitations of the Prototype approach
• Things people think will make others happy (goal-derived)

  • Birthday presents that make someone happy, items more likely to satisfy the goal indicated, bring maximum pleasure to recipient
• Best examples (prototypes)


  Shaped by ideal instances rather than average
• Exemplar approach


  Memory system storing a large number of specific instances, more stored instances of a concept make it easier to verify if it belongs in a category
• Exemplar approach focuses on specific instances rather than prototypes
• Study comparing prototypes vs exemplars (Storms et al., 2000)
• Embodied cognition approach


  Knowledge-based approach, coding a concept's features and knowledge about causal relationships between features
• Embodied cognition approach


  • 2 features of an ax - sharp, dangerous (related because an ax is dangerous due to its sharpness)
• Disease X and symptoms study (Ahn et al., 2000)
• Disembodied mind (Descartes)
• Human cognition = computer metaphor
• Bodily experiences play a fundamental role in shaping thoughts, emotions, perceptions
• Perceptual anticipation theory (Kosslyn, 2005)


  Same mechanisms for visual imagery and perception, similarity in neuropsychology, brain evidence
• Hub and spoke model
• Organisation of concepts into hierarchies and network
• Cognitive representation of semantic categories, memories
• Organisation of concepts


  1. Organised into hierarchies

  2. Organised into network
• Hierarchies


  • Basic level categories (e.g. chair) are most useful
  • Good balance between informativeness and distinctiveness
  • Most likely to rely on basic level labels to name pictures
• • Limitations of hierarchical organisation: 3 levels may not be enough
  • Basic level not always the go-to level
• Tanaka & Taylor, 1991

  For some cases, subordinate level (specific) is preferred over basic level
• Network


  • Spreading Activation Network (Collins & Loftus, 1975)
  • Nodes connected to other nodes with different lengths
  • Shorter connections indicate closer association and stronger activation
• Assessing semantic relatedness


  1. Word-association task

  2. Feature overlap

  3. Distance rating task
• Schemas


  • Configuration of combined concepts based on limited combination rules
  • Used to store and retrieve information from semantic memory
  • Set of related propositions forming a packet of typical knowledge about the world, events, people
• Uses of schemas


  1. Form expectations and take appropriate actions in the world

  2. Prevent cognitive overload

  3. Help fill in gaps in what we read/hear

  4. Assist when perceiving visual scenes, scene perception
• Rose & Frieze, 1989

  Script of Woman's first date vs Man's first date: More expectations/to-dos in man's script compared to woman's
• Bartlett, 1932


  Results of reproduction of culturally different story study: Memory distortions lead to remembering things consistent with schema and distorting things that are not consistent