Memory Chapter 7

Memory Studying Memory Building Memories An Information-Processing Model Two Memory Tracks Building Memories Encoding: Getting Information In Storage: Retaining Information Retrieval: Getting Information Out

Memory Forgetting Encoding Failure Storage Decay Retrieval Failure

Memory Memory Construction Improving Memory Misinformation and Imagination Effects Source Amnesia Children’s Eyewitness Recall Repressed or Constructed Memories of Abuse? Improving Memory

Memory is the persistence of learning over time through the encoding, storage and retrieval of information

Building a Memory To remember any information or experience requires: Encoding: getting information into our brain Storage: retaining the encoded information Retrieval: getting the information back out of memory storage

An Information-Processing Model A model of memory based on a computer (Atkinson & Shiffrin, 1968) Experience is first recorded, for just a moment, as a sensory memory Information is processed into short-term memory, encoded through rehearsal Holds a few items briefly Information moves to long-term memory for later retrieval

Updates to the I-P Model Some memories are formed through unconscious processing, without our awareness Working memory: a view of short-term memory that stresses conscious, active processes Working memory is not just a storage shelf, but an active desktop for linking new and old information

Two-Track Processing: Automatic vs. Effortful We automatically process vast amounts of everyday information We remember new and important information through effortful processing

Automatic Processing We automatically process information about Space “The definition was at the top of the right page” Time “I went to the store before lunch” Frequency “This is the third time I’ve seen her today!”

Effortful Processing Requires close attention and effort Memory can be improved through rehearsal, the conscious repetition of information Rehearsal was the subject of one of many studies of memory by Hermann Ebbinghaus

Ebbinghaus’s Experiment Studied his own learning and forgetting Used lists of nonsense syllables JIH, BAZ, FUB, YOX, SUJ, DAX, VUM, etc. Tested his memory for the list every day. The more he practiced out loud on day 1, the less time needed to relearn it on day 2

Effortful Processing Spacing effect: we remember better if study or practice is spread over time Cramming is less effective! Testing effect: repeated quizzing of previously studied material also helps

Serial Position Serial position effect: We remember the first and last items in a list best

Facts vs. Skills H.M. and others with certain traumatic brain injuries cannot form new explicit memories Cannot learn new facts However, they can learn new skills

Two-Track Memory Implicit memory: retaining skills or conditioning, often without conscious awareness Explicit memory: memories of facts and personal events that can be consciously retrieved

Two-Track Memory

Sleep and Memory Sleep supports memory consolidation During sleep, the hippocampus and cortex display rhythmic patterns of activity, as if communicating with each other The brain may be “replaying” the day’s experiences as it transfers them to the cortex for long-term storage

Building Memories Encoding: Getting Information In Storage: Retaining Information Retrieval: Getting Information Out

Encoding Meaning We may encode meaning rather than raw information When asked to recall text, we often report the meaning, or gist, rather than the raw text It can be difficult to remember things without a meaningful context

Encoding Images We can more easily remember things we can process visually as well as meaningfully Old Bailey (court in London)--Glen Bailey Memorable sentences often evoke powerful imagery, or mental pictures HOMES—the great lakes On Old Olympus' Towering Top, A Finn And German Viewed Some Hops—the cranial nerves: Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Spinal Accessory, Hypoglossal

Sensory Memory Storage is extremely short, especially for visual sensory memory Study: Sperling (1960) flashed nine letters for 1/20th of a second. Sensory memory made the letters momentarily available for encoding.

Short-Term Memory: Duration Study: Peterson (1959) presented 3-letter strings and prevented rehearsal Result: letters 50% gone at 3 seconds, 90% gone at 12 seconds. Conclusion—without rehearsal—doesn’t last long

Storage Capacities Short-term memory capacity is limited The Magical Number Seven, plus or minus two (George Miller, 1956) 7 digits or 7 chunks of information Long-term memory seems to have no limit and can endure for a lifetime

How Does the Brain Store Memory? Memory is not stored like books in a library, in neat, precise locations. Rather, different aspects of a memory are assigned to various groups of neurons. Thus, to understand how memory works, we must study the brain

Synaptic Changes Synapses are the sites where the signal from one neuron is received by another Experience modifies the brain’s neural network: increased activity in a pathway strengthens connections between the neurons involved

Synaptic Changes Kandel and Schwartz (1982) classically conditioned sea slugs to withdraw their tail when squirted with water (with electric shock). As the slug learned, serotonin was released into certain synapses. These synapses then become more sensitive and able to transmit signals more effectively.

Synaptic Changes Long-Term Potentiation (LTP): An increase in a synapse’s firing potential. A neural basis for learning and memory

Stress-Related Memories Excitement of stress can enhance memories. Stress  hormones  more available glucose to fuel brain activity  signals brain “something important has happened” Do you suppose that is why the pilot at Nellis AFB had found it much easier to count air craft on the ground when he made high speed-low altitude runs over airfields in hostile North Vietnam than in peaceful England?

Flashbulb Memories Emotion-triggered hormone changes help explain flashbulb memories, unusually clear memories of an emotionally significant moment or event Do you remember exactly where they were on September 11, 2001?

Retrieval: Getting Information Out Evidence that something has been remembered: The item can be recalled, on an essay exam The item can be recognized, as on a multiple-choice test Recognition memory is quick and vast Relearning the item may be easier than it was the first time

Retrieval Cues Memories are linked together in the brain, in a storage web of associations. These associations can serve as retrieval cues, any stimuli (events, feelings, places, etc.) linked to a specific memory We haven’t been at the GOP (Garden of Paradise) but thinking back—Al was at the cash register on that occasion. We’ve not been to Skewer’s for a couple years-but Hani showed us to our table. The more retrieval cues you’ve encoded, the better chance of finding a path to retrieve the memory

Context Effects Returning to the context where you experienced something can prime your memory of it Godden and Baddeley (1975) had scuba divers learn lists of words on land or underwater, and then attempt to recall them in the same or different context

Context Effects Sometimes being in a similar context to one previously experienced can trigger the eerie feeling of déjà vu (I’ve seen this before) This can happen when the current situation is loaded with retrieval cues that remind us of earlier, similar experiences Where was I went I originally learned this particular materials—in class or sitting at home

Moods and Memories Mood-congruent memory: we more easily recall experiences that are consistent with the current (good or bad) mood If we are in a good mood, we tend to remember good experiences Teen ratings of their parents are tightly linked to the teen’s current mood If your kid rates you as a parent after waking up grouchy, what kind of rating will he make?

Forgetting Jill Price is unable to forget anything. Why might this be a problem?

Seven Sins of Memory (Daniel Schacter, 1999) “Sins” of forgetting and retrieval, problems with the way memory works Absent-mindedness – inattention to detail leads to encoding failure Transience – memory loss as unused information fades Blocking – inability to access stored information

Seven Sins of Memory (Daniel Schacter, 1999) Sins of distortion Misattribution – confusing the source of information Suggestibility – e.g., asking a leading question influences answer and subsequent memory Bias – belief-colored recollections. Current feelings may alter a memory. Sin of intrusion Persistence – unwanted memories (e.g., PTSD)

Encoding Failure We cannot remember what we have not encoded

Storage Decay Forgetting is initially rapid, and then levels off People who had studied Spanish in high school but not after were tested on vocabulary recall One explanation may be a gradual fading of the memory trace, the physical changes in the brain as a memory forms

Retrieval Failure We can sometimes fail to retrieve a memory because we don’t have enough information to access the pathway to it

Interference Interference: the blocking of recall as old or new learning disrupts the recall of other memories Learning new passwords may interfere with remembering older ones Learning an hour before sleep can be good because of less interference (but still need rehearsal)

Forgetting Forgetting, the loss of information in between sensation and retrieval, can occur at any stages Sensory memory Short term memory Long term memory

Repressed Memories Freud argued that we repress, painful or unacceptable memories to minimize anxiety He argued that these repressed memories linger, and can be retrieved by some later cue or therapy Today, many memory researchers think repression rarely, if ever, occurs

Memory Construction Every time we “replay” a memory, we replace the original with a slightly modified version What implications does this have for everyday life? My wife and I can have very different memories of an event that we’ve both experience And that divergence may grow over time

Misinformation Misinformation effect: a memory that has been corrupted by misleading information Loftus and Palmer (1974) has subjects watch a film of a traffic accident. “How fast were the cars going when they smashed into each other?” or “How fast were the cars going when they hit each other?”

Misinformation People who were asked “smashed” version reported higher speeds A week later, they were more likely to (falsely) recall seeing broken glass

False Memory and Eyewitness Testimony Even hearing a vivid retelling of an event can implant false memories Sample of 200 convicts later proven innocent by DNA testing 79% misjudged based on faulty eyewitness identification Leading questions (“Did you hear loud noises”) can lead to false memories

Imagination and Memories Even imagining fake actions and events can create false memories College students were asked to imaging specific childhood events (like breaking a window with their hand). 25% later recalled the event as actually having happened. Possible cause: visualizing something and actually perceiving it activate similar brain areas

Source Amnesia Source amnesia: faulty memory for how, when, or where information was learned or imagined Sometimes experienced by songwriters and authors, who may unintentionally plagiarize something

Children’s Eyewitness Recall How can jurors decide cases in which children’s memories of sexual abuse are the only evidence? When 3 year-olds were asked to show on a doll where a pediatrician had touched them, 55% pointed to the genitals or anus, even though the doctor had not touched them there Use non-leading questions soon after the event, in language the child can understand

Repressed or Constructed Memories of Abuse Two tragedies concerning adult recollections of childhood abuse: When people don’t believe abuse survivors who share their secret When truly innocent people are falsely accused What about clinicians who help people “recover” memories of abuse?

Guidelines for Thinking about Recovered Memories of Sexual Abuse Sexual abuse happens Injustice happens Forgetting happens Recovered memories are commonplace Memories of things happening before age 3 are unreliable (Infantile amnesia) Memories “recovered” under hypnosis of under the influence of drugs are especially unreliable Memories, whether real or false, can be emotionally upsetting

Horror Carves a Memory The most common response to a traumatic experience is not to banish the experience into the unconscious. Rather, such experiences are typically etched on the mind as vivid, persistent, haunting memories.

Tips for Improving Memory Study repeatedly Space study sessions apart Spend more time rehearsing or actively thinking about the material Make the material personally meaningful Activate retrieval cues Minimize interference Sleep more Test your knowledge, both to rehearse it and to find out what you don’t know