Longterm Memory. Declarative Memory Consolidation and Sleep. Current Memory Models. Traditional Memory Models. Why Sleep?

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1 1 Longterm Memory Declarative Memory Consolidation and Sleep Kimberly Fenn Cognitive Psychology Psych 200 January 13, 2011 Declarative Memory Memory for facts, information, and events Procedural Memory Memory for skills, habits, and conditioning Traditional Memory Models Current Memory Models Short Term Store Long Term Store Short Term Store Consolidation Long Term Store After initial acquisition, memory remains in a weak or malleable state, susceptible to loss due to interference or decay 5 6 Why Sleep? Consolidation: the process by which memories are strengthened and stabilized, increasing resistance to interference and decay Absence of Sleep Impaired working memory Decreased arousal Increased RT to stimuli Real-world consequences Car accidents Comair Flight 5191 crash Exxon Valdez oil spill

2 7 8 Why Sleep? Proposed mechanism of consolidation: Offline processing Your brain works on information without any effort by you Sleep provides a physiological state during which offline processing can occur Consolidation of declarative memory during sleep Procedure: Paired Associates Task Participants studied 40 word pairs Cued Recall 40 word pairs Feedback given on every trial Error Correct response Trained to criterion: 60% correct CAMP - TRAIL BOOK - STORY CAT - TAIL GLACIER - SNOW TOAST - EGG TEAM - CREW GALE - WIND ANIMAL - FOX Delayed cued recall test 12 hours after training 9 10 Design Recall Performance Sleep Day 1 Day 2 9:00 21:00 9:00 Study I Waking Interval II Study I Sleep Interval II Number of correctly recalled word pairs No Evidence of Circadian or Diurnal differences in performance Declarative Memory and Sleep Recall Performance I Runs to Criterion Recall of information is better after sleep than it was prior to sleeping This effect is specific for an interval that includes sleep No improvement is seen after waking

3 14 A Memory. Bed Rest Awake Tired Dream Snooze Blanket Doze Slumber Snore Nap Peace Yawn Drowsy Declarative Memory and Sleep Sleep improves recall of paired associates Recall This effect is specific for an interval that includes sleep No improvement is seen after waking Does sleep simply strengthen a memory trace? Can sleep change the way that a memory is stored or the ability to use a memory? 16 Did you see the word snooze? Did you see the word dream? 17 18

4 Did you see the word lamp? Did you see the word sleep? The List Bed Rest Awake Tired Dream Snooze Blanket Doze Slumber Snore Nap Peace Yawn Drowsy If you remembered seeing the word Sleep then you experienced a false memory 21 Does sleep affect the formation of false or illusory memory? False Memory and Sleep Sleep may promote associative generalization Increased false memory Sleep may consolidate or strengthen true memory or prune false memory Reduced false memory 3 Studies with sleep manipulation DRM lists presented either Visually or Auditorally Visual recognition test Studied items Critical Lures Unrelated Lures SLEEP Bed Rest Awake Tired Dream Snooze Blanket Doze Slumber Snore Nap Peace Yawn Drowsy Critical Lure Correct memory (Studied items)

5 Results: Collapsed across experiments Day 1 Day 2 Condition 10:00 22:00 10:00 12 Hour 12 Hour Sleep Study Waking Interval Study Sleep Interval * * ** 25 * p<.05 compared to wake ** p <.01 compared to wake Fenn, et al., False Memory and Sleep in the DRM Paradigm Sleep reduces false memory without corresponding reduction in correct memory Is sleep strengthens an original memory, can it increase resistance to misleading information? Sleep may be enhancing memory for the source of the information 30 Misinformation Effect Procedure I. Study Ss watch film of two-car accident. II. Misinformation Ss estimate speed of cars when the cars... 1 week later: Did you see broken glass? smashed Ss hit Ss % yes (incorrect) 32% 14% a) smashed into each other or b) hit each other 41 mph 34 mph 29 (Loftus & Palmer, 1974)

6 31 32 Misinformation and Sleep Condition I: II: Movie Procedure 1. Video of robbery 2. Misleading information Questions about film 3. Recognition test Appeared in the film Unrelated lures Appeared only in questions (suggested memory) Two factors Retention interval Timing of misinformation At the beginning of the scene, a young man dressed in jeans, a t-shirt and gloves entered the house. Did he appear to be in a rush when he entered?" "Let s begin at the start of the scene again. At the beginning of the film clip, the young man who entered the house was dressed in jeans, a t-shirt and gloves. What color were the gloves?" Movie Misinformation 9:00 21:00 9:00 Movie Misinformation Sleep Correct Recognition False Recognition Proportion Hits Proportion False Recognition Misinformation and Sleep Sleep can have both positive and negative effects on memory If sleep can increase resistance to misleading information, will sleep deprivation decrease resistance? Sleep can protect memory from reconstruction When misinformation occurs after sleep, participants are better able to identify studied information and reject suggested information Sleep may increase false memory and increase memory reconstruction When misinformation occurs prior to sleep, false information may get consolidated with veridical memory

7 37 38 Sleep Deprivation Reduces working memory capacity Reduces frontal lobe function May reduce ability to acquire information Memory Susceptibility and Sleep Deprivation Procedure 1. View pictures that depict a story 2. Misleading information Read sentences that tell the same story, with false information 3. Multiple choice test 4. Source test Independent Variable Sleep vs. Sleep deprivation Sleep Deprivation Encoding Phase Math Learning Task Misinformation Math Free Recall Lab Arrival Set up for PSG Lights Out Lights On 48 hrs She showed her friend the new South Park DVD. Her friend did not approve of her selection. How does her friend react to her DVD selection? 22:00 00:00 02:00 06:00 08:00 10:00 10:00 She showed her friend the new South Park DVD. Her friend very much approved of her selection Source I saw it in the pictures only I saw it in the narrations only I saw it in both and they were the same I saw it in both and they conflicted with each other I guessed a)he seems pleased b)he seems displeased c)he seems neutral Mood Assessments Snack Correct memory for story elements False memory for suggested information

8 43 44 Robust False Memory Source I saw it in the pictures only I saw it in the narrations only I saw it in both and they were the same I saw it in both and they conflicted with each other I guessed Memory Susceptibility and Sleep Deprivation Memory performance is worse after sleep deprivation Correct memory for studied information is lower than after a full night of sleep Sleep deprivation increases susceptibility to misleading information 45 Thank you 46 Overall: Sleep and Memory Sleep can improve declarative memory for studied information In some cases, sleep may also decrease false memory or increase resistance to misleading information Sleep deprivation decreases memory performance for studied information Sleep deprivation increases susceptibility to misleading information Sleep is important. Study early. Do NOT pull an all-nighter before an exam! You will perform worse.