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PSY 368 Human Memory Memory Forgetting. Announcements Processing views homework due Web Feb 29 Craik and Lockhart (1972) download, read, and answer focus.

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Presentation on theme: "PSY 368 Human Memory Memory Forgetting. Announcements Processing views homework due Web Feb 29 Craik and Lockhart (1972) download, read, and answer focus."— Presentation transcript:

1 PSY 368 Human Memory Memory Forgetting

2 Announcements Processing views homework due Web Feb 29 Craik and Lockhart (1972) download, read, and answer focus questions, due Monday Feb 27

3 Forgetting Memory Performance Rapid forgetting for short delays - slower for longer delays Ebbinghaus (1885) Memory isn’t always perfect (remember The 7 Sins)

4 What do we forget ? Retrospective Autobiographical memory Prospective memory How do we forget ? Failure of Consolidation Failure of Retrieval Decay Interference Context/cue mismatch Forgetting

5 Hyperthymestic Syndrome Parker, Cahill, and McGaugh (2006) Case study of AJ, 41 years old Remembers every day of her life, in detail, since her teens. Feels as though she relives the events she remembers. Remembering feels “automatic” and not under conscious control. Can verify events with the diary she keeps. AJ’s superior memory has costs: She cannot forget unpleasant memories. Constant reminders are distracting and sometimes troubling. 5 Hyperthymestic Syndrome: Uncontrollable remembering Hyperthymestic Syndrome

6 We have seen pennies hundreds if not thousands of times. Draw one, the heads side. What do we forget? What does it say? Which way does the head face? Nickerson & Adams, (1979) Memory for the common penny quite bad. Less than half the people correctly identified its features

7 Everyday Memory Questionnaire Questions about things people typically forget Assesses memory abilities Typical score = 58 Higher scores indicate worse memory abilities for everyday tasks Has been used to assess memory deficits in brain injury patients Can also indicate possible dementia What do we forget? Average answers

8 Autobiographical Memory What do we forget? Recollected events that belong to a person’s past Personal milestones, emotional memories Why? Life narrative hypothesis – assume life identities during this time Cognitive hypothesis – encoding better in this period of rapid change Rubin (1982, 1996) “Hill of Reminiscence” Reminiscence bump : Adolescence/early adulthood (change to stability) Infantile amnesia

9 Autobiographical Memory What do we forget? Recollected events that belong to a person’s past Personal milestones, emotional memories The reminiscence bump for people who emigrated at age 34 to 35 is shifted toward older ages, compared to the bump for people who emigrated between the ages of 20 to 24 Schrauf & Rubin (1998) Cultural life shift – culturally shared expectations structure recall.

10 What do we forget? Measured the forgetting rate for people’s memory of widely publicized events from verifiable sources (headlines and TV broadcasts). Task : 14,000 participants completed an internet questionnaire, assessing recall and recognition for 1,000 dateable events. Results : Like the Ebbinghaus results, recall for events shows a steep initial drop, followed by a slower forgetting rate. Meeter, Murre, and Janssen (2005) Recall for events dropped from 60% to 30% in a year, then stayed constant. Recognition was overall better, but showed a similar pattern of results Recognition Recall

11 What do we forget? Permastore: Describes the leveling off of the forgetting curve at long delays. Beyond this point, memories appear impervious to further forgetting. Bahrick (1984) Permastore Rapid forgetting of foreign language for 3 yrs, Then of a asymptotes (levels off) after about 2 years, Stays fairly constant even up to 50 yrs. The overall level of retention is determined by the level of initial learning.

12 Bahrick, Bahrick & Wittlinger (1975) Permastore Tested nearly 400 high-school graduates on their ability to recognize and name classmates after delays of up to 30 years. Questions Recall Can you list all your classmates? Can you name all these faces? Recognition Is this the name of a classmate? Is this the face of a classmate? Match these names and faces

13 Bahrick, Bahrick & Wittlinger (1975) Permastore Tested nearly 400 high-school graduates on their ability to recognize and name classmates after delays of up to 30 years. Results were mixed : Relatively unimpaired: Ability to recognize their classmates’ faces/names. Ability to match up names to the appropriate portraits. Conclusion : Recall, but not recognition, of well-learned personal material, closely follows the forgetting curve first demonstrated by Ebbinghaus (1913). Extensively impaired: Ability to recall a name, given a person’s portrait. Recognition Name Matching Recall Name the picture 3.3 mons. 47+ yrs.

14 Bahrick studies Bahrick, Bahrick & Wittlinger (1975) – Studied memory of faces from high school. Bahrick & Phelps (1987) – Studied knowledge from school, learning Spanish and algebra. Bahrick, Bahrick, Bahrick, & Bahrick (1993) – benefits of distributed practice (13 or 26 sessions) on long term retention of 300 pairs of English and foreign words. Barhrick et al. (1996) – remembering high school grades, accurately remember A grades (89% accurate) but not D grades (29% accurate). Of Ps 79/99 inflated grades, more likely to remember positive events than negative events. Permastore

15 Skills Can vary in forgetting rate What do we forget? Taught flying skills, Flying a plane (simulated) Re-tested after 9 months, 1 year, and two years (no practice) Later performance was at same performance as it was following the initial training Very little forgetting of this skill Fleishman & Parker, 1962

16 What do we forget? McKenna & Glendon (1985) First aid volunteers who had mastered the skills Performance and timing Technique (inflate lungs and press chess in right place) Diagnosis (check breathing and pulse) Total score (would the patient have survived) Over time their CPR abilities drop very quickly Down to % within one yr Skills Can vary in forgetting rate Technique Performance Total score Diagnosis Months Percentage

17 Prospective memory (items 7, 14, 18) Remembering what you want to do ( event-based ) Remembering to do it at the right time ( time-based ) What do we forget? Retrospective memory Typically focused on What? questions Relatively new field of investigation, not as much known yet Guest speaker: Dr. Dawn McBride will tell us more in April “Various studies have reported that 50-80% of everyday memory problems are, at least in part, prospective memory problems” Kliegel & Martin (2003)

18 Prospective memory What do we forget? Have two tasks, a main task and a secondary task (the prospective task) “While you are performing this task (e.g., reading a list of words), if you see a word corresponding to an animal with fur, press the ‘1’ button” Typical Procedure

19 Prospective memory What do we forget? Einstein, McDaniel, Manzi, Cochran & Baker (2000) Task Primary: Read three sentences Secondary: press F1 key if read “technique” or “system” Either right away Or after a delay (~40 s later) Result Even with very short delay, a large drop in performance

20 Theories of forgetting: Failure of Consolidation Failure of retrieval Decay Context/cue mismatch Interference How do we forget?

21 Structural changes in the synaptic connections between neurons. Relies on biological processes May take hours to days to complete. Memories remain vulnerable until these changes occur. The gradual shift of a memory’s reliance away from the hippocampus and to the cortex. Accomplished by repeatedly “replaying” a memory’s various components until they are interlinked. May take years to complete in humans. Memories are vulnerable until they become independent of the hippocampus. Synaptic ConsolidationSystemic Consolidation Consolidation : The time-dependent process by which new memory traces are gradually cemented and interconnected in memory. Types of Consolidation

22 Sleep and Consolidation During sleep, neurochemical activity consolidating memories Retention of info is better if sleep follows study (Ekstrand, 1972) Empson and Clarke (1970) showed that when REM sleep vs. other sleep stages were interrupted, worse memory for info studied before sleep How do we forget?

23 Decay Info is lost from memory over time Applies to working memory and priming effects (activation levels). A potential biological basis of decay: Neurons die and synaptic connections degrade over time, along with the associated learned behavior. Trace decay is difficult to prove behaviorally because: It is necessary to rule out alternative sources of forgetting, including: Rehearsal Interference from any new experiences/memories. It is typically impossible to show whether the memories are unavailable or just inaccessible. How do we forget?

24 Context/cue mismatch See last lecture Failure to retrieve because cues available at retrieval and the ones present during encoding are different. How do we forget?

25 Interference (McGeoch, 1932) Info encoded before or after can interfere Storing similar memories impedes retrieval. Over time, many similar experiences occur, especially since people are creatures of habit. Two types: Retroactive = info that comes AFTER interferes Proactive = info that comes BEFORE interferes How do we forget?

26 Retroactive Interference (RI) How do we forget? Forgetting caused by encoding new traces into memory in between the initial encoding of the target and when it is tested. Introducing a related second list of items impairs recall of the first list compared to a control condition.

27 How do we forget? Dog – Book Tree - Cloud Shoe - Car Pen - Soda Clip - Horn Leaf - Cup Truck - Ant Fish - Goat Lake - Peach Recall from first list Dog – ? Tree - ? Shoe - ? Pen - ? Clip - ? Leaf - ? Truck - ? Fish - ? Lake - ? Dog – Bed Tree - Cake Shoe - Couch Pen - Stool Clip - House Leaf - Chair Truck - Apple Fish - Gas Lake - Penny

28 How do we forget? Dog – Book Tree - Cloud Shoe - Car Pen - Soda Clip - Horn Leaf - Cup Truck - Ant Fish - Goat Lake - Peach Recall from first list Dog – ? Tree - ? Shoe - ? Pen - ? Clip - ? Leaf - ? Truck - ? Fish - ? Lake - ? Dog – Bed Tree - Cake Shoe - Couch Pen - Stool Clip - House Leaf - Chair Truck - Apple Fish - Gas Lake - Penny Introducing a related second list of items impairs recall of the first list.

29 Proactive Interference (PI) How do we forget? The tendency for older memories to interfere with the retrieval of more recent experiences and knowledge. The number of previous learning experiences (e.g. lists) largely determines the rate of forgetting at long delays.

30 Demo Study the list of words on the front page (see the highlighted 1), one at a time, for 1 min. On a separate sheet of paper: Write down all the words from the 1st list - on front side - you remember Turn the paper over and study the list of words on the back page, one at a time, for 1 min.

31 How do we forget? List 1 Tulip Daisy Hydrangea Orchid Violet Magnolia Carnation Rose Lilac List 2a Dandelion Pansy Iris Gardenia Daffodil Lily Peony Geranium Marigold List 2b Cheetah Horse Skunk Llama Mouse Raccoon Lemur Rabbit Monkey

32 Rose…tulips…. Rose....horse… Same total number or items learned How do we forget? Release from PI (2nd list doesn’t interfere as much) Change in item type can release interference Learn 2 lists of flowers vs. 1 of flowers and 1 of animals

33 Summary (1)Tend to remember faces, languages, some skills for very long time - permastore (2)Identification forgotten (3)Forgetting due to decay and/or interference (retroactive, proactive) and/or lack of consolidation

34 Everyday memory Q (1)5 (2)1 (3)2 (4)2 (5)4 (6)3 (7)3 (8)3 (9)1 (10)2 (11)1 (12)1 (13)4 (14)2 (15)1 (16)3 (17)1 (18)2 (19)1 (20)2 (21)2 (22)2 (23)2 (24)2 (25)2 (26)1 (27)2 (28)1 Average ratings given by public in general Back to lecture


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