Short-Term vs. Long-Term Memory, Working Memory

I. STM vs. LTM II. Tripartite Model of WM III. Neuroimaging of WM e Short-term vs. Long-term Memory • primary memory: “the specious present”, refers to this moment in time • secondary memory: memories storehouse Distinctions between STM and LTM Active contents of Not currently in consciousness consciousness Active nodes in LTM Inactive until cued Heightened neural firing synaptic strength Unit-to-unit changes in relative to baseline Fast access to contents Slower access Limited capacity Unlimited capacity Modal Two-Store Model of Memory Atkinson & Shiffrin (1968) Serial Position Function in Free Recall Primacy Component – LTM Dissociable effects of study duration Rehearsal and Free Recall Recency Component – STM Dissociable effects of filled delay • Forward span (digits, words, symbols) – – – – 493759 6715247 05369417 265070193 – 8167049716 – 04862517290 • H.M. intact STM span, but impaired LTM The Fall of the Modal Model • Duration of maintenance/rote rehearsal doesn’t always predict LTM performance: impacts recognition but not recall – Rundus (1971) effects likely due to meaningful elaboration The Fall of the Modal Model LTM = incidental byproduct of processing of an event • LTM ≠ rehearsal time in STM • “deeper” processing = more effective and durable encoding • processing can be terminated at a particular level Levels of Processing Paradigm Levels of Processing: Subsequent Memory STM = Active Portion of LTM Control mechanisms maintain or keep active different memory representations such that they can be worked with in a goal-directed manner: Working Memory II. Tripartite Model of WM • • • Phonological WM Visuo-spatial WM Executive Control Working Memory Atkinson & Shiffrin (1971) “…we tend to equate the short-term store with ‘consciousness,’ that is, the thoughts and information of which we are currently aware can be considered part of the contents of the short-term store…Because consciousness is equated with the short-term store and because control processes are centered in and act through it, the short-term store is considered a working memory: a system in which decisions are made, problems are solved and information flow is directed.” Working Memory: What Do We Want to Know? Unitary vs. non-unitary WM? Nature of control in WM? Nature of representations in WM? What are the limits of WM? Biological implementation of WM? Tripartite Model of WM (Baddeley & Hitch, 1974) Separate WM Systems? Dual-task Double Dissociation Neuropsychological Double Dissociation The Phonological Loop What is the Nature of the PL? Neuropsychology & PL Sub-components Brain Bases of Phonological WM Component Processes and Brain Bases of Phonological WM Separating Rehearsal from Storage Component Processes and Brain Bases of Phonological WM fMRI Study of Relation between WM and LTM Relation between STM and LTM Do Meaning and Phonology Depend on Different WM Systems? Separable Semantic & Phonological WM? Visuo-Spatial Working Memory I. Distinguishing verbal from visuo-spatial WM II. Nature of representation and rehearsal in VSSP III. Visual vs. Spatial WM Dual-task Double Dissociation (van Heyer & Barrett, 1971) Distinguishing Verbal and Spatial WM What is the nature of the representations that are maintained in visuo-spatial WM? Representations in Visuo-Spatial WM What is the nature of rehearsal in visuo-spatial WM? Visuo-Spatial Selective Attention Rehearsal in Visuo-Spatial Working Memory Visual & Spatial WM: Unitary or Separable? Updated Understanding of Forms of WM