module 2
Bella edwards
myersep11e_lectureslides_ch08.pptxMemory
Chapter 8
EXPLORING PSYCHOLOGY
DAVID G. MYERS | C. NATHAN DEWALL
Chapter Overview
Studying and Encoding Memories
Storing and Retrieving Memories
Forgetting, Memory Construction, and Improving Memory
Studying and Encoding Memories
Memory
Persistence of learning over time through the encoding, storage, and retrieval of information
Evidence of memory
Recalling information
Recognizing it
Relearning it more easily on a later attempt
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Measuring Retention
Three measures of memory retention:
Recall: A measure of memory in which the person must retrieve information learned earlier, as on a fill-in-the-blank test.
Recognition: A measure of memory in which the person identifies items previously learned, as on a multiple-choice test.
Relearning: A measure of memory that assesses the amount of time saved when learning material again.
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Ebbinghaus’ Retention Curve
Ebbinghaus found that the more times he practiced a list of nonsense syllables on day 1, the less time he required to relearn it on day 2. Speed of relearning is one measure of memory retention (Baddeley, 1982).
Tests of recognition and of time spent relearning demonstrate that we remember more than we can recall.
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Memory Models (part 1)
Psychologists use memory models to think and communicate about memory.
Information-processing model
Compares human memory to computer operations
Involves three processes: encoding, storage, and retrieval
Connectionism information-processing model
Focuses on multitrack, parallel processing—the processing of many aspects of a problem simultaneously
Views memories as products of interconnected neural networks
Encoding: Process of getting information into the memory system.
Storage: Process of retaining encoded information over time.
Retrieval: Process of getting information out of memory storage.
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Memory Models (part 2)
Three processing stages in the classic Atkinson-Shiffrin (1968) model:
We record to-be-remembered information as a fleeting sensory memory, the immediate, very brief recording of sensory information.
We then process information into short-term memory (activated memory that holds a few items briefly), where we encode it through rehearsal.
Finally, information moves into long-term memory, the relatively permanent and limitless storehouse of the memory system of knowledge, skills, and experiences, for later retrieval.
Sensory memory: The immediate, very brief recording of sensory information in the memory system.
Short-term memory: Activated memory that holds a few items briefly, such as the seven digits of a phone number while calling, before the information is stored or forgotten,
Long-term memory: The relatively permanent and limitless storehouse of the memory system; includes knowledge, skills, and experiences.
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A Modified Three-Stage Processing Model of Memory
Atkinson and Shiffrin’s classic three-step model helps us to think about how memories are processed, but today’s researchers recognize other ways that long-term memories form. For example, some information slips into long-term memory via a “back door,” without our consciously attending to it (automatic processing). Also, so much active processing occurs in the short-term memory stage that many now prefer the term working memory.
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Memory Models (part 3)
Working memory
Stresses the active processing occurring in the second memory stage
Is a newer understanding of short-term memory that adds conscious, active processing of incoming auditory and visual-spatial information, and of information retrieved from long-term memory
In Baddeley’s (2002) model, this focused processing is handled by a central executive.
Encoding Memories
Dual-Track Memory: Effortful Versus Automatic Processing
Explicit memory (declarative memory): Memory of facts and experiences that one can consciously know and “declare.” We encode explicit memories through conscious effortful processing.
Implicit memory (nondeclarative memory): Retention of learned skills or classically conditioned associations independent of conscious recollection. We encode implicit memories through automatic processing, without our awareness.
Automatic Processing and Implicit Memories (part 1)
Implicit memories include procedural memory for automatic skills and classically conditioned associations among stimuli
Information is automatically processed about:
Space
Time
Frequency
Automatic Processing and Implicit Memories (part 2)
Automatic processing happens effortlessly.
With experience and practice, learned skills such as reading and driving become automatic.
Many skills are developed this way.
Effortful Processing and Explicit Memories
Sensory memory
Sensory memory feeds our active working memory, recording momentary images of scenes or echoes of sounds.
Two types of sensory memory are iconic memory and echoic memory.
Sensory Memory
Sensory memory: First stage in forming explicit memories
Iconic memory: Picture-image memory of visual stimuli lasting no more than a few tenths of a second
Echoic memory: Sound memory of auditory stimuli; can be recalled within 3 or 4 seconds
Total Recall—Briefly When George Sperling (1960) flashed a group of letters similar to this for one-twentieth of a second, people could recall only about half the letters. But when signaled to recall any one row immediately after the letters had disappeared, they could do so with near-perfect accuracy.
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Short-Term Memory Capacity
Short-term memory holds a few items briefly (such as the seven digits of a phone number while dialing) before the information is stored or forgotten.
George Miller (1956) proposed the magical number 7: People can store about seven bits of information (give or take two).
Baddeley and colleagues (1975) have confirmed that without distraction, we can recall about seven digits or about six letters or five words.
Capacity varies by age and distractions at the time of memory tasks.
Effortful Processing Strategies
Chunking: Organization of items into familiar, manageable units; often occurs automatically.
Mnemonics: Memory aids, especially techniques that use vivid imagery and organizational devices.
The peg-word system harnesses our superior visual-imagery skill.
Hierarchies: Organization of items into a few broad categories that are divided and subdivided into narrower concepts and facts.
Distributed Practice
Spacing effect: Encoding is more effective when it is spread over time.
Distributed practice produces better long-term retention than is achieved through massed study or practice.
Massed practice produces speedy short-term learning and feelings of confidence, but leads to quick forgetting.
Testing effect:
Enhanced memory after retrieving, rather than simply rereading, information.
Repeated self-testing (using the Retrieve It and Testing Effect questions in this text, for example) does more than assess learning: It improves it.
Practice may not make perfect, but smart practice—occasional rehearsal with self-testing—makes for lasting memories.
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Levels of Processing
Verbal information is processed at different levels, which affects long-term retention.
Shallow processing encodes on a very basic level (a word’s letters) or on a more intermediate level (a word’s sound).
Deep processing encodes semantically, based on word meaning.
The deeper (more meaningful) the processing, the better our retention.
Making Material Personally Meaningful
New information is processed easily when it is meaningful or related to our experience.
Ebbinghaus estimated that learning meaningful material requires one-tenth of the effort compared with learning nonsense material.
We have especially good recall for information we can relate to ourselves—a tendency referred to as the self-reference effect.
The amount of information remembered depends both on the time spent in learning it and on your making it meaningful for deep processing.
Memory Storage
Our capacity for storing long-term memories is essentially limitless.
This is contrary to the belief that we can add more items only if we discard old ones.
Retaining Information in the Brain (part 1)
Despite the brain’s vast storage capacity, we do not store information as libraries store their books, in single, precise locations.
Instead, brain networks encode, store, and retrieve the information that forms our complex memories. That is, the brain distributes the components of a memory across a network of locations in the brain.
Some of the brain cells that fired when we experienced something fire again when we recall it.
Retaining Information in the Brain (part 2)
We have two conscious memory systems:
Semantic memory: Explicit memory of facts and general knowledge
Episodic memory: Explicit memory of personally experienced events.
Hippocampus: A neural center located in the limbic system, which registers and temporarily holds elements of explicit memories before moving them to other brain regions for long-term storage
Memory consolidation: Neural storage of long-term memories
Explicit-Memory System: The Hippocampus
Explicit memories for facts and episodes are processed in the hippocampus (orange structures) and fed to other brain regions for storage.
The Hippocampus
Separate brain regions process explicit and implicit memories.
During sleep, the hippocampus and brain cortex display rhythmic patterns of activity, as if they were talking to each other (Euston et al., 2007; Mehta, 2007). Researchers suspect that the brain is replaying the day’s experiences as it transfers them to the cortex for long-term storage.
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Implicit Memory System: Cerebellum and Basal Ganglia
The cerebellum plays an important role in forming and storing implicit memories created by classical conditioning.
The basal ganglia—deep brain structures involved in motor movement—facilitate formation of our procedural memories for skills.
Infantile amnesia
Conscious memory of the first three years is blank.
Command of language and a well-developed hippocampus is needed for such memory.
The hippocampus is one of the last brain structures to mature.
The Amygdala, Emotions, and Memory
Excitement or stress triggers hormone production and provokes the amygdala (two emotion-processing clusters in the limbic system) to engage memory.
Emotions often persist with or without conscious awareness.
Emotional arousal causes an outpouring of stress hormones; the hormones lead to activity in the brain’s memory-forming areas.
Flashbulb memories—clear memories of emotionally significant moments or events—occur via emotion-triggered hormonal changes and rehearsal.
Key Memory Structures in the Brain
Frontal lobes and hippocampus: Explicit memory formation
Cerebellum and basal ganglia: Implicit memory formation
Amygdala: Emotion-related memory formation
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Synaptic Changes
Long-term potentiation (LTP)
Increase in a synapse’s firing potential after brief, rapid stimulation
After LTP, the brain will not erase memories
Believed to be a neural basis for learning and memory
Kandel and Schwartz (1982):
Observed synaptic changes during learning in the neurons of the California sea slug, Aplysia.
Pinpointed changes in sea slugs’ neural connections: With learning, more serotonin is released and cell efficiency is increased.
Aplysia
Aplysia, the California sea slug, which neuroscientist Eric Kandel studied for 45 years, has increased our understanding of the neural basis of learning and memory.
After LTP has occurred, an electric current passing through the brain won’t erase old memories—but the same current will wipe out very recent memories.
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Doubled Receptor Sites
Electron microscope image (a) shows just one receptor site (gray) reaching toward a sending neuron before long-term potentiation. Image (b) shows that, after LTP, the receptor sites have doubled. This means that the receiving neuron has increased sensitivity for detecting the presence of the neurotransmitter molecules that may be released by the sending neuron. (From Toni et al., 1999.)
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Our Two Memory Systems
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Memory Retrieval: Retrieval Cues
Memories are held in storage by a web of associations.
Retrieval cues serve as anchor points for pathways to memory suspended in this web.
When you encode into memory the name of the person sitting next to you in class, you associate it with other bits of information about your surroundings, mood, seating position, and so on.
The best retrieval cues come from associations formed at the time a memory is encoded.
Priming: Activation, often unconsciously, of particular associations in memory.
Retrieval Cues (part 1)
Priming
After seeing or hearing rabbit, we are later more likely to spell the spoken word hair/hare as h-a-r-e (Bower, 1986).
Associations unconsciously activate related associations.
Figure 8.13
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Retrieval Cues (part 2)
Context-dependent memory
Recall of specific information improves when the contexts present at encoding and retrieval are the same.
Cues and contexts specific to a particular memory will be most effective in helping recall.
Retrieval Cues (part 3)
State-dependent memory
Emotions that accompany good or bad events become retrieval cues.
Mood-congruent memory: The tendency to recall experiences that are consistent with one’s current good or bad mood.
Passions are exaggerated:
In a bad mood, we may read someone’s look as a glare and feel even worse.
In a good mood, we may encode the same look as interest and feel even better.
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The Serial Position Effect
Serial position effect: Our tendency to recall best the last (recency effect) and first (primacy effect) items in a list.
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Why Do We Forget?
William James (1890): “If we remembered everything, we should on most occasions be as ill off as if we remembered nothing.”
It’s surely a blessing that most of us discard the clutter of useless or out-of-date information—but our sometimes unpredictable memory can be frustrating.
Anterograde amnesia: Inability to form new memories.
Retrograde amnesia: Inability to retrieve information from one’s past.
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When Do We Forget?
Forgetting can occur at any memory stage.
When we process information, we filter, alter, or lose most of it.
Encoding Failure
Much of what we sense, we never notice.
What we fail to encode, we will never remember.
Age: Encoding lag is linked to age-related memory decline.
Attention: Failure to notice or encode contributes to memory failure,
You have surely seen the Apple computer logo thousands of times. Can you draw it? In one study, only 1 of 85 UCLA students (including 52 Apple users) could do so accurately (Blake et al., 2015). Without encoding effort, many potential memories never form.
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Forgetting as Encoding Failure
We cannot remember what we have not encoded.
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Storage Decay
Even after encoding something well, we sometimes later forget it.
The course of forgetting is initially rapid, but then levels off with time.
Physical changes in the brain occur as memory forms (memory trace).
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Ebbinghaus’ Forgetting Curve
After learning lists of nonsense syllables, such as YOX and JIH, Ebbinghaus studied how much he retained up to 30 days later. He found that memory for novel information fades quickly, then levels out. (Data from Ebbinghaus, 1885.)
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Retrieval Failure (part 1)
Sometimes even stored information cannot be accessed, which leads to forgetting.
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Retroactive Interference
More forgetting occurred when a person stayed awake and experienced other new material.
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Retrieval Failure (part 2)
Interference
Proactive (forward-acting) interference: Prior learning disrupts recall of new information.
Retroactive (backward-acting) interference: New learning disrupts recall of older information.
Motivated forgetting
Sigmund Freud argued that we repress painful or unacceptable memories to protect our self-concept and to minimize anxiety.
Today’s researchers think repression rarely, if ever, occurs.
Forgetting is more likely when information is neutral, not emotional; we often have intrusive memories of the very same traumatic experiences we would most like to forget.
Repression: In psychoanalytic theory, the basic defense mechanism that banishes from consciousness anxiety-arousing thoughts, feelings, and memories.
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Memory Construction Errors (part 1)
Memory is not precise. We don’t just retrieve memories, we reweave them.
Elizabeth Loftus and Katherine Ketcham (1994): “Our memories are flexible and superimposable, a panoramic blackboard with an endless supply of chalk and erasers.”
Reconsolidation: A process in which previously stored memories, when retrieved, are potentially altered before being stored again.
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Misinformation and Imagination Effects
Misinformation effect: Corruption of a memory by misleading information.
Even repeatedly imagining fake actions and events can create false memories.
Digitally altered photos can produce imagination inflation—that is, memories of events that people have not actually experienced.
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Memory Construction
In this experiment, people viewed a film clip of a car accident (left). Those who later were asked a leading question recalled a more serious accident than they had witnessed (Loftus & Palmer, 1974).
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Memory Construction Errors (part 2)
Source amnesia (source misattribution): Attributing to the wrong source an event we have experienced, heard about, read about, or imagined.
Source misattribution, along with the misinformation effect, is at the heart of many false memories.
Déjà vu: That eerie sense that “I’ve experienced this before.” Cues from the current situation may unconsciously trigger retrieval of an earlier experience.
Discerning True and False Memories
False memories feel like real memories and can be persistent, but are usually limited to the gist of the event.
False memories are often a result of faulty eyewitness testimony.
Memory construction helps explain:
Why dating partners who have fallen in love overestimate their first impressions of each other.
Why people asked how they felt 10 years ago about certain social issues recall attitudes closer to their current views than to the views they actually reported a decade earlier.
Children’s Eyewitness Recall
Studies by Ceci and Bruck (1993, 1995):
The effect of suggestive interviewing techniques.
How easily children’s memories can be molded: In one study, 58 percent of preschoolers produced false stories about one or more unexperienced events.
Children can often accurately recall events when nonleading questions are asked by a neutral person, in words the children can understand, and the questions are asked soon after the event (ideally before children have talked much to involved adults).
Can Memories of Childhood Sexual Abuse Be Repressed and Then Recovered? (part 1)
The debate between memory researchers and some well-meaning therapists focuses on whether most memories of early childhood abuse are repressed and can be recovered during therapy using “memory work” techniques that may involve “guided imagery,” leading questions, hypnosis, or dream analysis.
Two tragedies of child abuse:
When people don’t believe abuse survivors
When innocent people are falsely accused
There’s a need to find a sensible common ground.
Can Memories of Childhood Sexual Abuse Be Repressed and Then Recovered? (part 2)
Those committed to protecting abused children and those committed to protecting wrongly accused adults have agreed on the following points:
Sexual abuse happens.
Injustice happens.
Forgetting happens.
Recovered memories are commonplace, but this doesn’t necessarily mean the unconscious mind repressed them.
Memories of things happening before age 3 are unreliable.
Memories “recovered” under hypnosis or the influence of drugs are especially unreliable.
Memories, whether real or false, can be emotionally upsetting.
Improving Memory
The SQ3R (Survey, Question, Read, Retrieve, Review) study technique used in this book incorporates several learning strategies:
Rehearse repeatedly.
Make the material meaningful.
Activate retrieval cues.
Use mnemonic devices.
Minimize interference.
Sleep more.
Test your own knowledge, both to rehearse it and to find out what you do not yet know.
