Implicit Memory SNU CSE Son, Suil

Contents Question implicit memory vs. explicit memory Various ways of Experiment Can learning occur without awareness ? Evidence of implicit memory (by experimental dissociation) Theoretical accounts of implicit memory The Activation View Multiple Memory Systems Transfer Appropriate Processing The Bias View

Question Q1 : What is the main difference between implicit memory and explicit memory ? Q2 : How can we know that implicit memory and explicit memory are different ? Q3 : What are the good point and the weak point of 4 accounts of implicit memory ?

Implicit Memory vs. Explicit Memory Implicit memory is memory without awareness. Listening to music while doing other work. Explicit memory is memory with awareness. Preparing to exam We can discriminate these by experiment. (learning test)

Various ways of Experiment Test Instructions – PHASE II Indirect Direct Study (Learning) Instructions - PHASE I Incidental Cell 1 Cell 2 Intentional Cell 3 Cell 4 * Incidental vs. intentional – learning instruction * Indirect vs. direct – testing method * Implicit vs. explicit – type of memory used Cell 1 : subjects do not intentionally learn the testing items and are not aware of the relationship between the test and the study (learning) phase. So they do not try to recall the items on test. (usually implicit memory test) Cell 2 : subjects do not intentionally learn the testing items but on testing phase, they are instructed to recall the items just studied. Cell 3 : subjects instructed to memorize items on study phase, but they don’t try to memorize directly the items met previous phase. Cell 4 : subjects are asked to study items and on testing phase, are asked to recall the items just studied test. (usually explicit memory test)

Can learning occur without awareness? – 1 Markovian artificial grammar test By A.S. Reber. Type of Experiment intentional learning and direct test (Cell 4) Learning Group 1 : Learn Markovian grammar Group 2 : Does not Learn Markovian grammar Test Both group were tested to identify words whether they are grammatical or not Result : Group 1 was more accurate, but they can not verbalize what they learned Conclusion : Learning can indeed occur in the absence of awareness X S1 S1 S1 S1 S2 S1 S4 S1 S1 S T T T T T T T T X S1 P S1 S1 S6 P P P P P P P P P V S1 S1 S1 S1 S3 S5 S1 V T T T T T T T T T LETTERES GRAMMARTICAL ? TXS O PXS X TSPS TXXVV

Can learning occur without awareness? – 2 Type of Experiment incidental learning and direct test (Cell 2) Learning Pressing a sequence of dots appear in one of four locations (ex. 1-2-2-1, 4-3-1-3, …) Test Identify the sequence is old or new. (the pattern was shown previously or not) Fast presentation rate – can not use knowledge Slow presentation rate – can use knowledge Result For slow representation rate, subject were able to distinguish between old and new sequences Conclusion Learning can occur in the absence of awareness Old New Mean Confidence Rating Fast Slow

Experimental Dissociations Group 1 Group 2 Learning can occur without awareness but can we say that there is confidently implicit memory? We need to show that implicit memory is different from other memory (explicit memory) When experimental method is different and the test result is also different, then we can say that there is dissociation. Different learning instruction Intentional Incidental Different testing instruction direct indirect Different result 1 2 3 4

Dissociation experiment 1 (Tulving, Schacter, Stark) Phase I : learn a list of 96 words Group 1 : just playing with words (incidental learning) Group 2 : just playing with words (incidental learning, but more key words) Phase II-1 : 1 hour later Word-fragment completion test (indirect test) Completing words in mind Recognition test (direct test) Identify the word was shown or not previously Phase II-2 : 7 days later Same test for another 48 word Analysis of the result Better result for recognition test on 1 Hour later, is repetition priming obtained previous intentional learning. Conclusion : There is difference between indirect test and direct test There are implicit memory and explicit memory Probability of Response A B 1 Hour 7 Days A. Recognition (direct test) B. Fragment Completion (indirect test) * Repetition priming : Processing something as second time benefits from its having been processed previously

Dissociation experiment 2 (Graf, Schacter) Phase I : studied word pair Phase II : studied word pair Phase III : Test Group 1,2 - Direct test : Asked to complete the stem with the originally studied word. Group 1,2 - Indirect test : word-fragment completion with the first word that came to mind) Group 3. Only Phase III direct, indirect test (Base Line) Phase I Phase II Tested On Interference Control (Group 1) A-B C-D RI (Retroactive Interference) Experimental (Group 2) A-D PI (Proactive Interference) RI (Retroactive Interference) PI (Proactive Interference) Test Type Control (Group 1) Experimental (Group 2) Direct .55 .40 .67 .45 Indirect .34 .32 .35 Analysis of the result RI and PI affected direct tests of memory but did not affect indirect tests Conclusion : There is dissociation between indirect test and direct test. There are implicit memory and explicit memory

Theoretical accounts of implicit memory The Activation View Multiple Memory Systems Transfer Appropriate Processing The Bias View

The Activation View Indirect test is attributable to the temporary activation of preexisting representations. KEY WORD : Temporary The least popular of the four views Weak Point can not explain long time effects

Multiple Memory Systems Many dissociations between direct and indirect tests of memory arise because the tests tap different underlying memory systems. The assumption of multiple memory system. System Other Name Subsystems Characteristics Procedural Nondeclarative Motor skills Nonconscious operation (indirect) Cognitive skills Simple conditioning Simple associative learning Perceptual representation Visual word form Auditroy word form Structural description Primary memory Working memory Visual Conscious operation (direct) Auditory Semantic Generic Spatial Factual Relational Knowledge Episodic Personal Autobiographical Event memory

Transfer Appropriate Processing 4 assumption A given type of processing will lead to better memory performance if it is appropriate for the particular test Direct and indirect tests of memory typically require different retrieval operation Most indirect tests rely primarily on perceptual processing. Data driven Most direct tests rely primarily on the encoded meaning of concepts Conceptually driven Direct/Data Driven , Indirect/Data Driven , Direct/ Conceptually Driven , Indirect/Conceptually Driven Test Not multiple memory system (Direct vs. Indirect) Two Data Driven Test Result is Better Auditory Visual Visual Two Direct Better Data Driven Multiple System View Predict V Transfer Appropriate Processing Predict Result Direct/Conceptually Driven Direct/Data Driven Indirect/Data Driven Indirect/Conceptually Driven

The Bias View Other 3 views can not explain quite well especially the repetition priming effects. Prior presentation of an item can bias subsequent processing of the item on later presentations One is likely to interpret a stimulus in the same way as you have interpreted it in the past Bias entails both cost and benefits Cost : There will be an advantage if prior processing is appropriate for the current task Benefits : There will be a disadvantage if prior processing is inappropriate for the current task. Experiments : 2. Second See ambiguous woman 3. People are more likely to interpret the ambiguous picture as the same person as the unambiguous picture 1. First See Old Woman Young Woman 2. Second See Ambiguous -> Old Woman -> Young Woman 1. First See one of old woman and young woman

Summary Implicit memory is memory without awareness. There are various ways of experiment Learning can occur without awareness. We can say that Implicit memory is different memory from explicit memory by experimental dissociations. There is 4 main accounts for implicit memory

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