Memory: Persistence of learning over time through the storage and retrieval of information Memory depends on encoding, storing, and retrieving information STEPS: External events  sensory memory  short term/working memory  long term memory WM: Automatic or effortful encoding Can be aided by the timing of rehearsals, imagery, and mnemonic devices WM has short duration and limited capacity LTM: is limitless and constructive Works by leaving traces of neural impulses Long term potentiation  permanent change in synapses Stress hormones influence memory We have implicit (cerebellum) and explicit (hippocampus)LTM Retrieval of information happens by recall, recognition or faster relearning Priming (unconscious), context effects, and mood congruence help us retrieve relevant information

Answers to previous questions? When we learn new things, do we forget some of the old things “to make room”? No matter what we learn about “timing of rehearsals,” why do we learn much better just before an exam? Why do we remember details of events surrounding a traumatic experience so clearly? Why do we sometimes have the eerie sense that we have “lived this moment before” ?

Module 22 – Forgetting, Memory Construction and Improving memory What if we remembered everything?

Today’s interesting questions Do you think that you may have repressed some of your memories and that they may be resulting in some unexplained fears or anxieties? If you attended a French, German, or Italian language high school  Do you feel that your previous language skills are poorer now? How is that possible if memory is limitless? Do you remember stuff better if you work at night or in the morning? Should you memorize formulas or definitions the day before an exam or during the week before an exam? Did anyone ever lie about what they heard from you, or what they saw you do?

7 sins of the memory 3 sins of forgetting 3 sins of distortion Absent mindedness – failure to encode Transience – decay of storage Blocking – failure to retrieve 3 sins of distortion Misattribution – source of information Suggestibility – effects of misinformation Bias – current information influencing recall 1 sin of intrusion Persistence of unwanted memories

Forgetting as encoding failure Some information is encoded without effort Some information requires effortful encoding or it never enters long-term memory External events Sensory memory Short- term Long- Attention Encoding failure leads to forgetting

Forgetting as storage decay 1 2 3 4 5 10 15 20 25 30 40 50 60 Time in days since learning list Percentage of list retained when relearning Ebbinghaus forgetting curve: How much information is retained long term? Memory for novel information fades quickly over the first 3 days, then levels out.

Time in years after completion of Spanish course What if the information survives the first 3 days? Similar forgetting curve for Spanish vocabulary learned by students Retention drops, then levels off 1 3 5 9½ 14½ 25 35½ 49½ Time in years after completion of Spanish course 100% 90 80 70 60 50 40 30 20 10 Percentage of original vocabulary retained

Forgetting as retrieval failure Forgetting can result from failure to retrieve information from long-term memory External events Attention Encoding Retrieval failure leads to forgetting Retrieval Sensory memory Short-term Long-term

Retrieval failure: Interference Learning some items may disrupt retrieval of other information Proactive (forward acting) Interference disruptive effect of prior learning on recall of new information E.g., remembering the new phone number Retroactive (backwards acting) Interference disruptive effect of new learning on recall of old information E.g., learning new students’ names interfere with the recall of the names of previous students.

Effects of sleep on information retrieval Retroactive Interference is minimal during sleep Without interfering events, recall is better After sleep After remaining awake 1 2 3 4 5 6 7 8 Hours elapsed after learning syllables 90% 80 70 60 50 40 30 20 10 Percentage of syllables recalled

Retrieval failure: Motivated forgetting people unknowingly revise memories in self-serving ways. Repression We banish from consciousness anxiety-arousing thoughts, feelings, and experiences Widely held belief  legacy of Freud Memory researchers show that repression very rarely occurs

Forgetting Forgetting can occur at any memory stage As we process information, we filter, alter, or lose much of it

Memory Construction We filter information and fill in missing pieces Misinformation Effect: incorporating misleading information into one's memory of an event Imagination Effect: incorporating imagined events into one’s “memory”. Source Amnesia: attributing to the wrong source an event that we experienced, heard about, read about, or imagined (misattribution)

Misinformation Effect: Loftus experiment Eyewitnesses reconstruct memories when questioned Depiction of actual accident We imagine information as we tell. After repeated retellings, imagined information is incorporated in the memory. Leading question: “About how fast were the cars going when they smashed into / hit each other?” Memory construction

Source Amnesia The frailest aspect of memory is the source of information Imagination  recollection Source amnesia of preschoolers: an experiment Children did activities with “Mr. Science” Mothers read stories about Mr. Science. They recalled events that were only in the stories.

MEMORY IS RECONSTRUCTION Children as eyewitnesses Experiment by Ceci and Bruck: A list of some likely and some very unlikely events Children asked to think “very carefully” and report After 10 weekly interviews, 58% of preschoolers produced vivid false memories of unlikely events “Repressed” memories of abuse Clinicians point of view differ from that of memory researchers The difference in opinion has important legal and ideological ramifications It is common to forget experiences that are difficult to interpret We recover memories (good or bad) when cued We cannot reliably report about things that happened before the age of 3 – infantile amnesia Memories (real or false) can be stressful