PSYCH 45 lecture 4/26/2011 Tuesday, April 26, 2011 9:11 AM Wagner: Other Factors that Optimize Memory Factors that maximize short-term memory retention often result in poorer long-term retention Can lead to overestimation of learning Optimal learning requires "desirable difficulties" What maximizes long-term retention? Retrieval during study: tests are the best study events Spaced practice The Generation Effect READ Conditions: Synonym: Unhappy -- SAD Rhyme: Pad -- SAD Generate Conditions: Synonym: Unhappy -- S___? Rhyme: Pad -- S___? Greater elaboration/processing of meaning or phonology Greater engagement of retrieval processes during study that are likely to be engaged at test Power of Retrieval as an Encoding Event: Roediger & Karpicke 2006 Subjects were given a text passage to learn Three study conditions SSSS: four study presentations SSST: three study presentations followed by one test STTT: one study presented followed by three tests Wither 5 minutes or 1 week later Asked how well they felt they had learned the material Then tested on how well they retained the ideas from the passage Judgments of Learning (JOL) Subjects in SSSS felt that they had learned the material better than the other groups Memory performance Testing promotes better long-term retention than repeated studying Distributions of Practice Not all encoding events are created equal "with any considerable number of repetitions a subtle distribution of them over a space in time is decidedly more advantageous than the massing of them at a single time (Ebbinghaus 1885) Spacing effect: greater lags between practice/study trials yield better memory Understanding Distributed Practice Deficient processing: during massed/short lag trials, the second occurrence of an item is not processed fully Less attention to items just processed Encoding variability: longer lags result in more variable encoding Variable encoding yields a richer memory trace permitting access from multiple routes Variability may derive from random stimulus/context fluctuations across time (Estes' stimulus sampling theory) Summary: Optimal Learning Strategies Attend to the information Attend to the meaning of events; relate new information to other things you know Practice retrieving the target information from memory Distribute your study episodes across time Neural Bases of Episodic Encoding Define Amnesia (retrograde, anterograde) Examine role of the medial temporal lobe Consolidation Definition of Amnesia Anterograde Amnesia: the inability to remember new events Retrograde Amnesia: the inability to recollect memories acquired before the brain injury Medial temporal lobe damage (H.M. & E.P.) The MTL Circuit - Apex of Information Flow Hierarchy GLOBAL Learning Impairment in Medial Temporal Lobe Amnesia Material Specific Amnesia following Unilateral Lesions of the MTL Left hemisphere: verbal learning (linguistic, semantic) Right hemisphere: nonverbal learning (spatial, visual) MTL Structures and Episodic Memory Patient RB had damage to only one region (CA1) of the hippocampus Damage limited to the hippocampus can cause amnesia As an extent of MTL damage increases, the amnesic syndrome becomes more severe However, doesn't mean that all MTL structures mediate the same function Medial Temporal Lobe Memory System: Relational Memory Theory The MTL, in interaction with neocortical storage sites, supports conjunctive memory binding and activation, representing the relations among perceptually distinct items of scenes or events, and mediating their retrieval Relational Memory Theory Hippocampus, in interaction with the parahippocampal region (MTL cortex) and neocortical processors, supports declarative memory --> memory for facts & events Declarative memory is a fundamentally relational system Hippocampus contributes the critical processes of relational memory binding & activation of conjunctions It represents & retrieves all manner of relations among the elements of experiences, events, or scenes It rapidly acquires (1-trial learning) these representations Representations are flexibly addressable Parahippocampal region contributes to memory for individual items Multiple routes to memory Intact Recombined New/forgotten MTL and Retrograde Amnesia MTL damage impairs not only new learning, but also disrupts memories acquired before the injury (retrograde amnesia) Retrograde Amnesia - Consolidation Temporally-graded loss of pre-morbid memories Ribot's law 1881 Consolidation: processes that transform a memory trace into a durable representation that is not dependent on the MTL Sleep-dependent reactivation? Declarative Memory During REM sleep, hippocampal firing patterns replay patterns present during the animal's day
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