Memory I Long-term memory & Encoding

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Memory I Long-term memory & Encoding. Are there multiple LTM memory systems?. How do you learn a new skill? How do you learn a new fact? How about learning about an event? Is there one long-term memory (LTM) system for these types of knowledge or are there multiple LTM systems?.
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Memory ILong-term memory & EncodingAre there multiple LTM memory systems?
  • How do you learn a new skill?
  • How do you learn a new fact?
  • How about learning about an event?
  • Is there one long-term memory (LTM) system for these types of knowledge or are there multiple LTM systems?
  • A Taxonomy of Memory SystemsLONG TERM MEMORYEXPLICIT(declarative)IMPLICIT(non-declarative)SEMANTIC(facts)EPISODIC(events)PRIMING(perceptual,conceptual)PROCEDURAL(skills & habits)ASSOCIATIVE LEARNING(classical & operant conditioning)Medial Temporal LobeCortexStriatumAmydala/ CerebellumImplicit and explicit memory
  • Implicit memory:
  • past experiences influence perceptions, thoughts & actions without awareness that any information from past is accessed
  • Explicit memory:
  • conscious access to info from the past (“I remember that..” ) -> involves conscious recollectionExplicit & Implicit Memory TestsLook at the following words. I will test your memory for these words in various ways.Memory Test
  • Explicit test of memory: recall
  • Write down the words you remember from the list in the earlier slide
  • Implicit tests of memory
  • On the next slide, you will see some words missing letters, some “word fragments” and some anagrams. Guess what each word might be.
  • Implicit Memory Tasks
  • Word-fragment completion is an implicit memory task.Fragments are (often) completed with words previously studied in the absence of an explicit instruction to remember the word
  • Amnesiacs often showed spared implicit memory
  • dissociation suggest different systems for implicit and explicit memory systemsImplicit vs. Explicit Memory
  • Graf, Squire, & Mandler (1984):
  • Study words: cheese, house, …
  • Explicit memory test: cued recall. Complete fragment to a word from study list:
  • ch _ _ _ _
  • Implicit memory test: word stem completion. Complete fragment to form any word: ch _ _ _ _
  • Word-stem completion spared in amnesiacsGraf et al. (1984).AmnesiaSources
  • Blow to head, Concussion
  • Korsakoff syndrome (severe vit. B1 deficiency)
  • Alzheimer’s
  • Damage to hippocampus, thalamic structures
  • ECT (electroconvulsive shock therapy)
  • Midazolam: artifically induced amnesia
  • Amnesia
  • Types:
  • Retrograde: cannot remember old memories
  • Anterograde: cannot form new episodic memories
  • Retrograde amnesia
  • Temporal gradient:
  • early memories are better remembered than memories before trauma (Ribot’s law)
  • Recently formed memories continue to undergo neurological change: memory consolidation
  • Retrograde amnesia often becomes less severe over time
  • Most remote memories are likely to return first
  • Does not affect overlearned information (e.g. skills)
  • Temporal Gradient
  • Memory for diary entries from retrograde amnesic
  • (Butters & Cermak, 1986)Anterograde Amnesia
  • Inability to acquire new information
  • Think of movie “memento”
  • Does not affect short-term memory
  • Does not affect general knowledge from the past
  • But, it is difficult to learn new facts
  • Affects memory regardless of modality (visual, auditory, tactile, etc).
  • Spares skilled performance
  • Famous Anterograde Amnesiac: HM
  • Severe epilepsy
  • Treated with surgery to bilaterally remove medial temporal lobes, including hippocampus
  • Operation 9/1953, 27 years old
  • A NPR segment on HM
  • Henry Gustav MolaisonH.M
  • General knowledge intact but “stuck in time”.
  • Did not learn words introduced after 1953: “Jacuzzi”, “granola”, “flower-child”
  • Was able to form some memories
  • Initially couldn’t learn how to get to his new home. But after several years, he was able to draw make detailed map of his residence.
  • Showed sensitivity to long-term repetition priming
  • Could learn to mirror reverse read and mirror trace
  • HM able to mirror traceimprovement in H.M. for mirror tracing task (without conscious recollection of previous training episodes) the medial temporal lobes are not necessary for all types of long-term memory.Milner, 1965 Can amnesics acquire any new knowledge? Declarative memory (memory for information/knowledge, e.g. episodic & semantic memory)  impairedProcedural memory (e.g., how to ride a bike)  yesImplicit memories (using past information possibly without being aware of it)  yesLearning a new skill: mirror-reverse readingAmnesics can learn to mirror-reverse read and are sensitive to repetitions Spared (implicit) learning in anterograde amnesia
  • Claparede study (1911).
  • Patient never remembered having met Claparede (doctor) before
  • Claparade offers handshakes with pinprick
  • Next time, no explicit memory of event (or doctor)
  • Still, patient refuses to shake hands and offers explanation: “sometimes pins are hidden in people’s hands”
  • Korsakoff patients & Trivia questions
  • Given feedback, then retested. No conscious memory for items but better performance. “I read about it somewhere”. (Schacter, Tulving & Wang, 1981).
  • Encoding & Retrieval EffectsLevels of ProcessingLevels of processing effect:Deeper levels of processing (e.g., emphasizing meaning) tend to lead to better recall. (Craik & Lockhart, 1972)Encoding Specificity Principle
  • Recollection performance depends not only on how the information was encoded but also how the way the information is retrieved at test
  • Encoding specificity principle: recollection depends on the interaction between the properties of the encoded event and the properties of the retrieval information
  • (Related to “transfer appropriate processing”)Role of Context
  • Information learned in a particular context is better recalled if recall takes place in the same context
  • Similarly, information learned in a particular context may be difficult to recall in a dramatically different context
  • Role of ContextMemory experiment with deep-sea divers
  • Deep-sea divers learned words either on land or underwater
  • They then performed a recall test on land or underwater
  • Godden & Baddeley (1975, 1980)Mood-dependent Memory
  • Easier to remember happy memories in a happy state and sad memories in a sad state.
  •  mood primes certain memory contents “sad” state“happy” stateKenealy (1997).State-dependent recall
  • Does physical state matter?
  • Eich et al. (1975): study while smoking normal or marijuana cigarette. Test words under same or different physical condition
  • The Spacing Effect
  • Massed practice: many trials with the same stimulus are undertaken without interruption.
  • Distributed practice: the trials with the same stimulus are separated by other stimuli.
  • Spacing effect:Memory is better for repeated information if repetitions occur spaced over time than if they occur massed, one after another
  • One explanation for spacing effect
  • Encoding variability
  • in subsequent encounters of a stimulus, different aspects of a stimulus are selected for encoding
  • Because spacing increases encoding variability, there are more ways in which information can be accessed and retrieved
  • Spacing EffectsSpaced repetitions better for long term retention.Massed better for short term retention.Long-term effects of spacing
  • Bahrick et al. (1993). Authors studied foreign language vocabulary for four years and tested themselves over the next five years.
  • During study, items were repeated in 14, 28, 56 day intervals.
  • Results: even 5 years after study, words studied in 56 day intervals were recalled 50% more than words studied in 14 day intervals.
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