How Many Memory Stores Are There? PDF created with pdffactory trial version

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1 How Many Memory Stores Are There?

2 Outline The serial position curve The modal model Empirical evidence: manipulations and dissociations The modal model: critique Single-store models Two-store vs. single-store models: where do we stand?

3 The Serial Position Curve Percent Correct free recall Serial Position Ben Murdock (1962), Journal of experimental psychology

4 Memory Stores James (1890): primary memory, secondary memory Agreement on the existence of LTM Agreement on the existence of a sensory store Controversy re: STM

5 The Brown-Peterson Paradigm 1.0 Proportion correct Distractor Duration Fig 3.3

6 The Modal Model (Atkinson & Shiffrin, 1968; Waugh & Norman, 1965) Input Sensory Memory STM Elaborative Rehearsal LTM Maintenance Rehearsal *Account for the serial position curve

7 Short-Term Memory Capacity limitation Rehearsal, chunking Type of processing My problem is that I have been persecuted by an integer

8 Long-Term Memory in the Modal Model Maintenance vs. Elaborative rehearsal Effortful/effortless Capacity; forgetting; retrieval failure Type of processing

9 Rehearsal and the Primacy Effect Direct manipulation of rehearsal (Hellyer, 1962) 7382 Repeat a word 3 to 27 times 60 trials, surprise recall Memory # repetitions Overt Rehearsal (Rundus, 1971) Predictions for late serial position items?

10 Manipulations in Healthy People List length (Postman & Phillips, 1965; Glanzer & Cunitz, 1966) Proportion correct 10 items 20 items Serial position

11 Manipulations in Healthy People Presentation rate (Murdock,1 962; Raymond, 1969) Predictions for Semantic similarity?

12 Single and Double Dissociations Behavioral and neuropsychological dissociations Why are double dissociations important? Examples for the complementary single dissociation

13 Manipulations in Healthy People Immediate vs. delayed testing End-of-the-list distractor task (Glanzer & Cunitz, 1966)

14 Manipulations in Healthy People Output order (Dalezman, 1976)

15 Manipulations and Dissociations: Brain Damaged People Hippocampal damage (Baddeley & Warrington, 1970) H.M Intact digit span, immediate story recall Impaired delayed story recall Parietal damage (Warrington & Shallice, 1969) K.F

16 Serial Position Effects and the Patients underwent anterior temporal lobectomy for relief of epileptic symptoms Administered listlearning task before and 6 months after surgery Hippocampal tissue examined for sclerosis Hippocampus

17 Serial Position Effects and the Hippocampus Hermann et al., 1996

18 The Short-Term Memory Syndrome Patients with selective impairment of phonological STM Defective performance on the final positions of supra-span auditorilypresented list Intact performance on visually-presented sequences (Vallar& Papagno, 1986) Percent Correct Serial Position

19 Alternative Interpretation for PV s Data: Recall from end Percent Correct Percent Correct Serial Position Auditory presentation Serial Position Visual presentation

20 The Modal Model: Critique First trial of Brown-Peterson Paradigm shows no forgetting Distractor Duration

21 Continuous Distractor Recall Bjork & Whitten (1974) *real-life example Study: Each list consisted of 13 word pairs Interpolated activity consisted of simple arithmetic problems Conditions: Interpolated activity: 0-sec Vs. 12-sec Length of filled retention interval: 0 sec Vs. 30 sec

22 Continuous Distractor Recall Bjork & Whitten (1974) No interpolated activity 12-sec interpolated activity Serial Position Serial Position

23 Single-Store Memory Models Short term recency (immediate testing) Long-term recency: In real life (Baddeley& Hitch, 1977) The continuous distractortask (Bjork & Whitten, 1974) More parsimonious: able to explain the data without requiring a second memory store Models using The contextual retrieval hypothesis Distinctiveness

24 Contextual Retrieval When an item is encoded, its memory trace is linked to its encoding context. The context at time t is more similar to the t-1 context than to the t-2 context. Recall probability is a function of the similarity of encoding and retrieval contexts. t-2 t-1 t

25 Distinctiveness Models The recall probability of an item is a function of the item s distinctiveness along a certain dimension, or a combination of dimensions

26 Single-Store Explanations for the Serial Position Curve Primacy: rehearsal & contextual/distinctiveness advantage Recency: higher distinctiveness of late serial position items, or higher similarity between the encoding context of these items and the test context Can explain dissociations like The effects of end-of-list distractor task Output order

27 Forgetting in amnesia: Abnormal vulnerability to proactive interference? Memory in amnesia: Abnormal forgetting with filled delay (1 minute); forgetting whenever distracted Cowan et al. (2004): patients and controls studied 4 stories and were tested immediately, AND after a 1-hour FILLED or EMPTY delay (2 trials per condition)

28 Patients 1 and 5 snored during the unfilled delay

29 The Modal Model Where Do We Stand? The Demise of Short-Term Memory The burden of evidence should be with those who say these two, similar recency effects are caused by different mechanisms (Crowder, 1982) The composite view Different mechanisms for long-term and shortterm recency; STM is still necessary to explain short-term recency

30 LTM-Recency in the STM List of anagrams, each followed by an arithmetic task. Across experiments, PV shows impaired STM-recency coupled with intact LTMrecency. Syndrome

31 Carlesimo et al., 1996 CD and Immediate recall Compared 10 amnesics to age matched controls Etiology: head trauma (N=7), Aneurysm (N=1), Unknown (N=2) Groups had similar mean years of education

32 Carlesimo et al., 1996 Findings: Intact STM-recency but impaired LTMrecency? OR perhaps LTMrecency is also intact? Single-store theories like to think of a relative effect; dual store theories -absolute effect

33 How Many Memory Stores Are There? Outline The serial position curve The modal model Empirical evidence: manipulations and dissociations The modal model: critique Single-store models Two-store vs. single-store models: where do we stand? The Serial Position Curve Percent Correct free recall Serial Position Ben Murdock (1962), Journal of experimental psychology 1

34 Memory Stores James (1890): primary memory, secondary memory Agreement on the existence of LTM Agreement on the existence of a sensory store Controversy re: STM The Brown-Peterson Paradigm 1.0 Proportion correct Distractor Duration Fig 3.3 The Modal Model (Atkinson & Shiffrin, 1968; Waugh & Norman, 1965) Input Sensory Memory STM Elaborative Rehearsal LTM Maintenance Rehearsal *Account for the serial position curve 2

35 Short-Term Memory Capacity limitation Rehearsal, chunking Type of processing My problem is that I have been persecuted by an integer Long-Term Memory in the Modal Model Maintenance vs. Elaborative rehearsal Effortful/effortless Capacity; forgetting; retrieval failure Type of processing Rehearsal and the Primacy Effect Direct manipulation of rehearsal (Hellyer, 1962) 7382 Repeat a word 3 to 27 times 60 trials, surprise recall Memory # repetitions Overt Rehearsal (Rundus, 1971) Predictions for late serial position items? 3

36 Manipulations in Healthy People List length (Postman & Phillips, 1965; Glanzer & Cunitz, 1966) Proportion correct 10 items 20 items Serial position Manipulations in Healthy People Presentation rate (Murdock,1 962; Raymond, 1969) Predictions for Semantic similarity? Single and Double Dissociations Behavioral and neuropsychological dissociations Why are double dissociations important? Examples for the complementary single dissociation 4

37 Manipulations in Healthy People Immediate vs. delayed testing End-of-the-list distractor task (Glanzer& Cunitz, 1966) Manipulations in Healthy People Output order (Dalezman, 1976) Manipulations and Dissociations: Brain Damaged People Hippocampal damage (Baddeley & Warrington, 1970) H.M Intact digit span, immediate story recall Impaired delayed story recall Parietal damage (Warrington & Shallice, 1969) K.F 5

38 Serial Position Effects and the Hippocampus Patients underwent anterior temporal lobectomy for relief of epileptic symptoms Administered listlearning task before and 6 months after surgery Hippocampal tissue examined for sclerosis Serial Position Effects and the Hippocampus Hermann et al., 1996 The Short-Term Memory Syndrome Patients with selective impairment of phonological STM Defective performance on the final positions of supra-span auditorilypresented list Intact performance on visually-presented sequences (Vallar& Papagno, 1986) Percent Correct Serial Position 6

39 Alternative Interpretation for PV s Data: Recall from end Percent Correct Percent Correct Serial Position Auditory presentation Serial Position Visual presentation The Modal Model: Critique First trial of Brown-Peterson Paradigm shows no forgetting Distractor Duration Continuous Distractor Recall Bjork & Whitten (1974) *real-life example Study: Each list consisted of 13 word pairs Interpolated activity consisted of simple arithmetic problems Conditions: Interpolated activity: 0-sec Vs. 12-sec Length of filled retention interval: 0 sec Vs. 30 sec 7

40 Continuous Distractor Recall Bjork & Whitten (1974) No interpolated activity 12-sec interpolated activity Serial Position Serial Position Single-Store Memory Models Short term recency (immediate testing) Long-term recency: In real life (Baddeley& Hitch, 1977) The continuous distractor task (Bjork& Whitten, 1974) More parsimonious: able to explain the data without requiring a second memory store Models using The contextual retrieval hypothesis Distinctiveness Contextual Retrieval When an item is encoded, its memory trace is linked to its encoding context. The context at time t is more similar to the t-1 context than to the t-2 context. Recall probability is a function of the similarity of encoding and retrieval contexts. t-2 t-1 t 8

41 Distinctiveness Models The recall probability of an item is a function of the item s distinctiveness along a certain dimension, or a combination of dimensions Single-Store Explanations for the Serial Position Curve Primacy: rehearsal & contextual/distinctiveness advantage Recency: higher distinctiveness of late serial position items, or higher similarity between the encoding context of these items and the test context Can explain dissociations like The effects of end-of-list distractor task Output order Forgetting in amnesia: Abnormal vulnerability to proactive interference? Memory in amnesia: Abnormal forgetting with filled delay (1 minute); forgetting whenever distracted Cowan et al. (2004): patients and controls studied 4 stories and were tested immediately, AND after a 1-hour FILLED or EMPTY delay (2 trials per condition) 9

42 Patients 1 and 5 snored during the unfilled delay The Modal Model Where Do We Stand? The Demise of Short-Term Memory The burden of evidence should be with those who say these two, similar recency effects are caused by different mechanisms (Crowder, 1982) The composite view Different mechanisms for long-term and shortterm recency; STM is still necessary to explain short-term recency LTM-Recency in the STM Syndrome List of anagrams, each followed by an arithmetic task. Across experiments, PV shows impaired STM-recency coupled with intact LTMrecency. 10

43 Carlesimoet al., 1996 CD and Immediate recall Compared 10 amnesics to age matched controls Etiology: head trauma (N=7), Aneurysm (N=1), Unknown (N=2) Groups had similar mean years of education Carlesimoet al., 1996 Findings: Intact STM-recency but impaired LTMrecency? OR perhaps LTMrecency is also intact? Single-store theories like to think of a relative effect; dual store theories -absolute effect 11