Psychology
Takemymoney
myers_pel4e_lectureslide_ch07.pptx7
Memory
Revised by Pauline Davey Zeece, University of Nebraska-Lincoln
Chapter Overview
Studying memory
Building memories: Encoding
Memory storage
Retrieval: Getting information out
Forgetting
Memory construction errors
Improving memory
Memory
Persistence of learning over time through the encoding, storage, and retrieval of information
Information-processing model
Compares human memory to a computer’s operation
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Stages in Information-Processing Model
Encoding
Getting information into the memory system
Storage
Retaining encoded information over time
Retrieval
Getting information out of memory storage
Information-Processing Model: Stages in Forming Memories
Recording to-be-remembered information as a fleeting sensory memory
Processing information into short-term memory, where it is encoded through rehearsal
Moving information into long-term memory for later retrieval
Sensory memory: Immediate and very brief recording of sensory information in the memory system
Short-term memory: Activated memory that holds a few items briefly before the information is stored or forgotten
Long-term memory: Relatively permanent and limitless storehouse of the memory system
Includes knowledge, skills, and experiences
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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 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).
And so much active processing occurs in the short-term memory stage that many now prefer to call that stage working memory.
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Working Memory
Newer understanding of short-term memory
Includes the conscious and active processing of:
Incoming information
Information retrieved from long-term memory
Working memory is more efficient when individuals focus on one task at a time, without distractions.
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Want to try to see how good your working memory is?
In Class Demonstration
Two-Track Memory System
Implicit (nondeclarative) memory
Retention of learned skills, or classically conditioned associations, without conscious awareness
Formed via automatic processing
Explicit (declarative) memory
Retention of facts and personal events that can be consciously retrieved
Formed via effortful processing
Building Memories
Automatic processing and implicit memories
Implicit memories include automatic skills and classically conditioned associations.
Effortful processing and explicit memories
Explicit memories become automatic with experience and practice.
This Photo by Unknown author is licensed under CC BY.
Your two-track mind processes information efficiently via parallel processing, which involves processing of many aspects of a problem at the same time.
This method is the brain’s natural mode of information processing for many functions.
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Sensory Memory
First stage in forming explicit memories
Records immediate and very brief information and is fleeting in nature
Iconic memory - Picture-image memory of a scene
Echoic memory - Sensory memory of sounds
Capacity of Short-Term and Working Memory
Short-term memory
Miller proposed that individuals can store about seven bits of information during the short-term stage.
Other researchers confirmed that individuals can recall about seven digits or about six letters or five words without distraction.
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Short-Term Memory Decay
Unless rehearsed, verbal information may be quickly forgotten.
Data from Peterson & Peterson, 1959; see also Brown, 1958.
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Effortful Processing Strategies
Chunking: Organizing items into familiar and manageable units
Occurs naturally
Mnemonics: Memory aids
Includes techniques that use vivid imagery and organizational devices
Effortful processing requires closer attention and effort, and chunking and mnemonics help us form meaningful and accessible memories.
Memory researchers have also discovered other important influences on how we capture information and hold it in memory.
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Memory Storage
Retaining information in the brain
Synaptic changes
Retaining Information in the Brain
Capacity for storing long-term memories has no real limit.
Research findings
Information is not stored in a single and specific spot.
Memories as neural networks
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The Hippocampus
Explicit memories for facts and episodes are processed in the hippocampus (orange structure) and fed to other brain regions for storage.
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Explicit and conscious memories are either semantic or episodic.
Semantic memory: Explicit memory of facts and general knowledge
Episodic memory: Explicit memory of personally experienced events
Explicit Memory System
Hippocampus: Neural center located in the limbic system
Helps process explicit memories for storage
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Explicit Memory System: The Frontal Lobes
Memories migrate for storage via the memory consolidation process.
Right and left frontal lobes store different information.
A good night’s sleep supports memory consolidation.
Slow-wave sleep
Memory consolidation: Neural storage of a long-term memory
Separate brain regions process explicit and implicit memories.
From the rhythmic patterns of activity displayed by the hippocampus and the brain cortex, researchers have posited that the brain is replaying the day’s experiences as it transfers them to the cortex for long-term storage.
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Hippocampus Hero
Among animals, one contender for champion memorist would be a mere birdbrain—the Clark’s Nutcracker—which, during winter and spring, can locate up to 600 caches of pine seed it had previously buried.
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Implicit Memory System: The Cerebellum and Basal Ganglia
Cerebellum
Plays an important role in forming and storing memories created by classical conditioning
Basal ganglia
Help form memories for physical skills, which are also implicit memories
As adults, our conscious memory of our first four years is largely blank, an experience called infantile amnesia. To form and store explicit memories, we need a command of language and a well-developed hippocampus. Before age four, we don’t have those learning tools.
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Retrieve and Remember
Your friend has experienced brain damage in an accident.
He can remember how to tie his shoes but has a hard time remembering anything you tell him during a conversation.
How can implicit versus explicit information processing explain what’s going on here?
ANSWER: Our explicit conscious memories of facts and episodes differ from our implicit memories of skills (such as tying shoelaces) and classically conditioned responses. The parts of the brain involved in explicit memory processing may have sustained damage in the accident, while the parts involved in implicit memory processing appear to have escaped harm.
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Effect of Emotions on Memory Processing
Excitement or stress triggers hormone production.
It provokes the amygdala to boost activity in the brain’s memory-forming areas.
Flashbulb memories: Clear memories of emotionally significant events
Occur via emotion-triggered hormonal changes
Retained due to rehearsal
Flashbulb memory: Clear memory of an emotionally significant moment or event.
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Review 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
Synaptic Changes: Kandel and Schwartz
More serotonin is released during learning.
The cell’s synapses become more efficient, which increases the efficiency of neural networks.
The number of synapses increases with experience and learning.
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Synaptic Changes
Long-term potentiation (LTP): Increase in a synapse’s firing potential
Believed to be a neural basis for learning and memory
After LTP, a current passing through the brain would not erase old memories.
Before LTP, an electric current that passes through the brain can wipe out very recent memories.
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Figure 7.7 - Our Two Memory Systems
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Retrieval: Getting Information Out
Measuring retention
Retrieval cues
Measuring Retention
Recall: Memory demonstrated by retrieving information learned earlier
Fill-in-the-blank test
Recognition: Memory demonstrated by identifying items previously learned
Multiple-choice test
Relearning: Memory demonstrated by time saved when learning material for a second time
Our recognition memory is quick and vast.
Indicators of memory strength include:
Response speed when recalling or recognizing information
Speed at relearning
Tests of recognition and of time spent relearning demonstrate that we remember more than we can recall.
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Ebbinghaus’ Retention Curve
The more times Ebbinghaus practiced a list of nonsense syllables on day one, the less practice he needed to relearn it on day two.
Speed of relearning is one way to measure whether something was learned and retained.
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Retrieving a Memory
Memories are held in storage by a web of associations.
Retrieval cues serve as anchor points for pathways that can be followed to access a memory.
The best cues come from associations formed at the time of encoding.
Priming: Activation, often unconsciously, of particular associations in memory
Retrieval cues: Any stimulus (event, feeling, place, and so on) linked to a specific memory
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Retrieval Cues
Memories are context dependent.
Affected by the cues that are associated with a specific context
State-dependent memory
What is learned in one state can be easily recalled if the individual is in the same state.
Mood-congruent memory: The tendency to recall experiences that are consistent with an individual's current good or bad mood
Mood effects on retrieval help explain why our moods persist.
When happy, we recall happy events and see the world as a happy place, which prolongs our good mood.
When depressed, we recall sad events, which darkens our view of current events.
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Forgetting
Forgetting and the two-track mind
Encoding failure
Storage decay
Retrieval failure
When Do We Forget?
Forgetting can occur at any memory stage.
When we process information, we filter it, alter it, or lose much of it.
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Forgetting and the Two-Track Mind
Humans have two distinct memory systems controlled by different parts of the brain.
Reasons for forgetting include:
Encoding failure
Storage decay
Retrieval failure
Amnesia: Loss of memory, often due to brain trauma, injury, or disease
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Which on is th face of the penny?
Forgetting as Encoding Failure
We cannot remember what we have not encoded.
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Storage Decay
The course of forgetting is initially rapid and then levels off with time. It is explained by the gradual fading of the physical memory trace.
Memory trace: Lasting physical change in the brain as a memory forms
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Retrieval Failure
Sometimes even stored information cannot be accessed, which leads to forgetting.
It stems from interference and motivated forgetting.
Events and memories are not available because they were never acquired. Other memories are discarded due to stored memory decay.
Sometimes, the memory is out of reach because individuals do not have enough information to access it.
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Motivated Forgetting
According to Freud, people repress painful or unacceptable memories to protect their self-concept and minimize anxiety.
Memory researchers think that people:
Succeed in forgetting unwanted neutral information
Struggle to forget emotional events
Repression: In psychoanalytic theory, the basic defense mechanism that banishes from consciousness the thoughts, feelings, and memories that arouse anxiety
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Errors in Memory Construction
Memory is not exact.
One doesn’t just retrace memories, one reweaves them.
Reconsolidation: The process in which previously stored memories, when retrieved, are potentially altered before being stored again
All memories are false to some degree.
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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.
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Source Amnesia
Faulty memory for how, when, or where information was learned or imagined
Helps explain déjà vu
An eerie sense that “I’ve experienced this before”
Cues from the current situation may unconsciously trigger retrieval of an earlier experience.
Recognizing False Memories
False memories are hard to separate from real ones because they seem real.
Can be persistent
Repeated retellings of an event may make individuals feel like they had actually observed them.
People easily remember the general idea, rather than the exact words.
Memory construction errors seem to be at work in many recovered memories of childhood abuse.
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Methods to Improve Memory
Rehearse repeatedly.
Make the material meaningful.
Activate retrieval cues.
Use mnemonic devices.
Minimize proactive and retroactive interference.
Sleep more.
Test your own knowledge.
Test your own knowledge, both to rehearse it and to find out what you do not yet know.
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