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Introduction to Long-Term Memory Psychology 355: Cognitive Psychology Instructor: John Miyamoto 4/30 /2015: Lecture 05-4 This Powerpoint presentation may contain macros that were used to create the slides. The macros aren’t needed to view the slides. If necessary, you can disable the macros without any change to the presentation.
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Outline Distinction between short-term memory and long-term memory HM – a famous clinical case Different types of long-term memory ♦ Explicit versus implicit memory (declarative vs non-declarative memory) ♦ Episodic versus semantic memory ♦ Procedural memory ♦ Associative memory Evidence for distinction between STM & LTM Evidence for distinction between episodic and semantic memory Evidence for distinction between explicit memory and implicit memory. Psych 355, Miyamoto, Spr '15 2 Lecture possibly ends here Picture Showing the STM/LTM Distinction
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Psych 355, Miyamoto, Spr '15 3 Figure 6.1: Example of the STM/LTM Distinction LTM STM Diagram of Modal Memory Model – Encoding, Retrieval & Consolidation
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Psych 355, Miyamoto, Spr '15 4 Encoding, Retrieval & Consolidation Encoding – creating an LTM out of currently processed information. Retrieval – bringing information that is stored in LTM back to STM Consolidation - creating a strong LTM by repeatedly retrieving and manipulating an LTM; and by associating it with other memories. Sensory Store Short-Term Store Long-Term Store Retrieval Encoding External World Control Processes List of Functions That Are Included in LTM
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Psych 355, Miyamoto, Spr '15 5 LTM Includes..... Important information about the self and events in the world, but also,... Trivial information about what has happened in the recent past, “Semantic” knowledge, e.g., what is an apple, a pencil; which is bigger, a mouse or a moose; etc. How to do things: Tie your shoes, drive a car, dial a phone number, cook a meal,.... Learned associations that are not explicit, e.g., the atmosphere of a dentist’s office makes you feel apprehensive. Diagram Showing the Major Components of the LTM System
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Psych 355, Miyamoto, Spr '15 6 Different Types of Long-Term Memory Figure 6.12. Different Types of Long-Term Memory Declarative memory (explicit memory) – facts, knowledge, images Non-declarative memory (implicit memory) – non-conscious memory that is expressed through change in behavior; it doesn’t necessarily include conscious recollection. Intro to HM
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Psych 355, Miyamoto, Spr '15 7 HM – A Famous Clinical Case HM – initials of a man See links to his biography on the Psych 355 website. Intractable epilepsy. August 25, 1953: Medial temporal lobes (left and right) were surgically resectioned to treat his epilepsy. Removal of the hippocampus. Following surgery, HM had much milder symptoms of epilepsy, but...... he was found to have severe problems with memory.. Where is the Hippocampus?
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Psych 355, Miyamoto, Spr '15 8 Where is the Hippocampus? HM underwent bilateral removal of much of the hippocampus, amygdala and surrounding medial temporal cortices. Schematic head facing up. Hippocampi are in red. This slide is based on instructional material that was downloaded from the Pearson Publishers website (http://vig.prenhall.com) for Smith & Kosslyn (2006; ISBN 9780131825086). HM’s Memory Problem Amygdala Hippocampus
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Psych 355, Miyamoto, Spr '15 9 HM’s Memory Post-Surgery HM could carry on a conversation, understand current situations. Severely impaired memory for any events occurring after brain injury. Some impaired memory for events occurring before injury. Could learn new skills like sewing. Could learn some new semantic information, e.g., his brain surgery was in 1953, but he learned that there was a president named Kennedy who was assassinated. Diagram Showing Multiple Memory Systems
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Psych 355, Miyamoto, Spr '15 10 Episodic & Semantic Memory Memory Terminology – Including Types of Amnesia SHORT-TERM MEMORY HUMAN MEMORY
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Psych 355, Miyamoto, Spr '15 11 Some Memory Terminology Explicit memory (declarative memory) ♦ Episodic memory - memory for personal experiences ♦ Semantic memory - memory for facts Implicit memory (non-declarative memory) ♦ Priming – exposure to one stimulus can affect ability to perform a cognitive task. ♦ Procedural memory - memory for how to do things, e.g., type at a computer. ♦ Associative and non-associative learning Amnesia ♦ Anterograde – amnesia for events occurring after brain injury. ♦ Retrograde - amnesia for events occurring before brain injury. Back to HM’s Memory Problems Discussed on Earlier Slide
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Psych 355, Miyamoto, Spr '15 12 HM's Memory Problems Anterograde amnesia – very severe; he could not form new permanent episodic memories. Retrograde amnesia – very severe for preceding 4 days; some impairment up to 11 year preceding. ♦ Retrograde amnesia was temporally graded, i.e., less amnesia as you go farther into the past. ---------------------------------------------------- Declarative memory – severely impaired ♦ Episodic memory – very severe ♦ Semantic memory – severe but he could still learn some new general facts. Procedural memory – relatively intact ♦ HM learned to sew. ♦ HM learned to draw mirror images. Diagram Showing that HM’s Memory Problem Pertains to Encoding
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Psych 355, Miyamoto, Spr '15 13 HM's Explicit Memory Problem (Remember that this diagram is an over-simplification) HM's worst problem was encoding from STM (WM) to LTM. Impaired transfer from STM to LTM. STM (WM) was still functioning because he could understand the current situation. Note: This diagram omits the role of the hippocampus in consolidation (probably HM had difficulty with consolidation as well as encoding). Sensory Store Short-Term Store Long-Term Store Retrieval Encoding External World Control Processes How Do We Know that STM & LTM Are Different Mechanisms?
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Psych 355, Miyamoto, Spr '15 14 How Do We Know that STM and LTM Involve Different Brain Mechanisms? Evidence from the Serial Position Curve: Subject views list of 20 words, one word at a time. Each word is presented for 2 seconds. After viewing the list, subject attempts to recall as many words as possible. Curve shows the percentage of times a word in each position was recalled correctly. Interpretation of Standard Result for Serial Position Curve Serial Position % Recalled Figure 6.3 Serial Position Curve
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Psych 355, Miyamoto, Spr '15 15 Interpretation of Standard Result for Serial Position Curve Claims (to be substantiated in subsequent slides) Primacy effect is due to transfer to LTM. Recency effect due to words retained in STM. Standard result for serial position curve is evidence for STM/LTM distinction. How to Prove that Primacy is Due to Transfer to LTM? Serial Position % Recalled Figure 6.3 Serial Position Curve Primacy Effect Recency Effect
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Psych 355, Miyamoto, Spr '15 16 How to Prove Primacy Effect Is Due to Transfer to LTM? Rundus (1971) presented words at the rate of 1 word per 5 seconds. 20 words in the list. Subjects were instructed to rehearse words aloud. What Subject SeesWhat Subject Says carcar, car, car,... stonecar, stone, car, stone, car,... topcar, stone, top, car, stone, top,............................ This study has 2 dependent variables: ♦ Frequency of recall for words in each position ♦ Number of rehearsals for words in each position Results for Rundus Experiment
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Psych 355, Miyamoto, Spr '15 17 Figure 6.4 to the right: Red solid line: Serial position curve (standard result) Blue dotted line: Number of times a word in each position was rehearsed. Blue dotted line correlates perfectly with the serial position curve (red dotted line) except for the recency effect. This supports claim that primacy effect is due to transfer to LTM. Results for Rundus (1971) Study Figure 6.4 Effect of Overt Rehearsal % Recalled Serial Position Number of Rehearsals How to Prove that Recency Effect Due to Retention in STM?
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Psych 355, Miyamoto, Spr '15 18 How to Prove Recency Effect Is Due to Retention in STM? Dashed line shows effect of counting backwards by 3’s for 30 seconds after presentation of list. Counting backwards prevents retention of words in STM, so recency effect disappears. This result supports the hypothesis that the recency effect is due to retention of recent words in STM. Serial Position Figure 6.5 Effect of Counting Backwards % Recalled How We Know that STM & LTM Are Different Mechanisms - Summary No recency effect Glanzer, M., & Cunitz, A. R. (1966). Two storage mechanisms in free recall. Journal of Verbal Learning and Verbal Behavior, 5, 351-360.
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Psych 355, Miyamoto, Spr '15 19 How Do We Know that STM and LTM Involve Different Brain Mechanisms? (Conclusion) Assumption of separate STM & LTM explains facts about the serial position curve. Neuropsych evidence of double dissociation between STM & LTM. o HM & Clive Wearing had normal memory span, e.g., 5-8 digits o KF had reduced memory span, e.g., about 2 digits. LTM was ok. Surprise Memory Test Items STMLTM HM, Clive WearingOKImpaired K. F.ImpairedOK
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Example (to be discussed later) ELK SHIP PEAR Psych 355, Miyamoto, Spr '15 20 Diagram of Memory Systems – Next: Episodic vs Semantic Memory
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Psych 355, Miyamoto, Spr '15 21 Episodic & Semantic Memory Next Topic: There are two types of explicit (declarative) memory: Episodic memory is memory for the experience of events in one's personal history. Semantic memory is memory for facts, events, and knowledge that is not linked to a specific personal experience. Episodic vs Semantic Memory – Some Examples
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Psych 355, Miyamoto, Spr '15 22 Thursday, April 30, 2015 : The Lecture Ended Here
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