Do all these faces look familiar? Can you name them all? Why is it difficult to recall names even though you can recognize them? More generally, why do we forget things?
Learning Causes Forgetting: Interference Theory (very little evidence of decay in LTM)
Release from Proactive Interference Interference in LTM w/ Brown-Peterson task 18 seconds retention interval a switch between class of material at 4 th, 7 th, or 10 th trial
Semantic Coding in LTM (continue with fruits versus switching to new category)
Tests of Long-term Memory free recall (in any order) requires a search through memory cued-recall (paired associate learning) study: FLAG-SPOON, DRAWER-SWITCH, etc. test: FLAG-, DRAWER- results are similar to free recall recognition how to measure performance? increased hits (saying old to targets) could be a bias to always say old compare hit rate to the false alarm rate false alarms are saying old to distractors (aka foils or lures) signal detection theory
Recognition and Source Knowledge Remember/Know vs Confidence I recognize you from the party remember judgments very high confidence You look familiar, but I don t know why know judgments moderate confidence
Context Effects recall is better in the same context as study encoding specificity Thomson and Tulving (1970) word context e.g., studied ground-cold» better recall with ground-? than hot-? Godden and Baddeley (1975) environmental context
The Memory Network Spreading Activation can explain why two retrieval cues are better than one Subthreshold activity Sums Subthreshold activity
The Memory Network Lexical Decision Task (Semantic priming)
Context Reinstatement (just thinking about the original context can help retrieval)
List Learning Results differences between recognition and recall Common words are easy to recall but hard to recognize Context effects are larger for recall memory for longer lists is worse (list length effect) A,B,C vs. A,B,C,D,E,F memory is better when stimuli are studied longer (strength effect) A,B,C vs. A,A,A,B,B,B,C,C,C distributed study is better than massed study spacing effect A,A,A,B,B,B,C,C,C vs. C,A,B,A,B,C,B,A,C Encoding variability recall memory is worse when other stimuli are studied longer (list-strength effect) A,B,C vs A,BBB,CCC however, this doesn t occur for recognition
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Different Kinds of LTM
Misattribution of Implicit Familiarity Seeing a photo before a lineup causes false identification Reading names can result in false fame after a delay Reading w/o attention produces the same effect immediately Reading made-up factoids causes illusion of truth Even when explicitly told that a subset of the factoids are false 0.7 0.6 0.5 0.4 0.3 0.2 Famous New 1 x 4 x 0.1 0 Immediately One day
Amnesia
Causes of Amnesia Bilateral damage to the medial temporal lobes (including the hippocampus) inability to make new memories (anterograde amnesia) partial retrograde amnesia (period just before damage) sources of damage permanent: Surgery, stroke, hypoxia, head injury, encephalitis progressive: Korsakoff s syndrome, Alzheimer s, tumors, CTE temporary: electroconvulsive therapy (ECT), benzodiazepines hippocampal versus parahippocampal damage recall versus familiarity
Anterograde Amnesia (what can an Amnesic learn?) general knowledge and personal history are frozen poor at recall, recognition, etc. no new vocabulary (e.g. jacuzzi, granola, etc.) intact STM / working memory all modalities affected preserved skill learning Implicit learning, but no explicit memory (dissociation) procedural versus declarative motoric or perceptual (i.e., cannot learn chess) rotary pursuit mirror tracing mirror image reading reading of new words (but no knowledge of meaning) long-term priming (stem and fragment completion)
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Retrograde Amnesia (what does an amnesic forget?) the period just before the injury is forgotten temporally graded retrograde amnesia memory consolidation (Squire) memories are temporarily hippocampally dependent with time, the cortex learns the memories this process is called memory consolidation
Double Dissociation? SMO46: explicit memory with no fear WC1606: fear with no explicit memory Controls show both explicit memory and a fear response.