Memory
pp. 235-249, 249-260, 265-269
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• What is memory?
• Memory processes
– Encoding
– Storage
– Retrieval
• Types of memory
• Models of memory
What is memory?
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• All of the info in your head and the processes that allow you to encode,
retain, recall and use that info
– Memory is the Cognitive Psychology answer to the learning proposed by
behaviorism
How Do We Study Memory?
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• Hypothetical construct, not a tangible one
– You can’t directly observe “memory”
Basic Memory Processes
Memory Processes
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• Our memories work like computers (or libraries)
– Encoding: Transforming information into a form that can be entered and retained
– Storage: Retaining information in memory to be used later
– Retrieval: Recovering information
Encoding
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• Acoustic encoding: mental representation of information as sounds
• Visual encoding: mental representation of information as images
• Semantic encoding: mental representation of an experience by its meaning
Deeper processing = better recall
Semantic > Acoustic > Visual
Encoding
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• Repetition
– Glenberg, Smith & Green (1977)
• Elaboration
– Memory works by creating an internal representation of the world. The effectiveness
of this representation depends in how rich it is
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Retrieval
• Recall:
– Retrieving information not in our conscious awareness
• Cued recall:
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– Remembering with retrieval cues
• Recognition:
– Identifying information you’ve already seen or heard
• Performance
– Acts influenced by previous information (priming)
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• http://www.youtube.com/watch?v=dMFsuBlkoIQ&mode=related&search=
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Types of Memory
• Episodic memory:
– memory of an event that occurred while you were present
– It is stored as a story
• Semantic memory:
– generalized knowledge of the world
– It is stored as facts
• Procedural memory:
– memory of how to do something
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Implicit vs. Explicit Memory
Explicit Memory
• Process of intentionally trying to remember something
• Memory with awareness
• Info or knowledge that can be consciously recollected
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Implicit Memory
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Unintentional influence of prior experience
Memory without awareness
Remembering things you’ve already seen or done
Priming: facilitation of performance
How Does Memory Work?
• Levels of Processing
• Transfer-Appropriate Processing
• Parallel Distributed Processing (PDP)
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• Information Processing
Levels of Processing Model
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• Maintenance rehearsal
– Repeating over and over
• Elaborative rehearsal
– Relating new material to info already stored
Study Tips
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Don’t underline in your textbook
Don’t study by reciting material only to yourself
Don’t cram
Do take notes while reading text
Do study with another person or group of people
Do organize the info along the way (like the island rating)
Transfer-Appropriate Processing
• Transfer-appropriate processing
– Memory is enhanced when retrieval processes match encoding processes
– Scuba study
– Exam study
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Parallel Distributed Processing
• Parallel distributed processing
– New experiences change overall knowledge base
• Neural networks
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Parallel Distributed Processing
Models of Memory
• Information processing
– Information passes through sensory, short-term, & long-term memory
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Stages of Information Processing
• Sensory
– Info from senses held for brief time
• Short-term memory (STM)
– Perceived info held for about 20 seconds
• Long-term memory (LTM)
– Further processed & remains indefinitely
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Stages of Memory
• Sensory registers
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– Temporary storage bins
– One for each sense
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Short Term Memory
• STM:
– holds info transferred from sensory memory and retrieved from long-term memory
• Working memory:
– part of memory system that allows us to manipulate info in STM
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Short Term Memory
• Encoding in STM
– Acoustic encoding
– Visual encoding
– Kinesthetic encoding
• Listen to these words…
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Short Term Memory
• Despite the “magical number” some people have remarkable memory and
can remember many more numbers
• Chunks
– Meaningful groups of related items
– Increases amount of information retained
• What was the last number we memorized?
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Forgetting in
Short-Term Memory
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Duration of Short-Term Memory
• Information retained up to 18 seconds before being forgotten
• Information can be held longer if it is rehearsed or repeated over and over
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Long Term Memory
• A relatively long-lasting memory with unlimited capacity to store new
information
• Usually is the result of a more elaborate and conscious encoding
– Implicit memory is long term and is not conscious
– Some detail of episodic memory or semantic memory can also be remembered
without an explicit effort
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Semantic Encoding
• Which is farther east: San Diego or Reno?
• Which is farther north: Seattle or Montreal?
• Which is further west: The Atlantic or the Pacific entrance to the Panama
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Canal?
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Organization of Info in LTM
• Information is clustered
– Clustering: organizing items into related groups or clusters
– recite the days of the week
– recite the days of the week in alphabetical order
• Information is associated
– Logical links among different bits and pieces of information
– Recall as many words as possible
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Distortions of Long Term Memory
• College students were asked to recall their high school grades
– They correctly remembered 89% of their A grades but only 29% of their D grades
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Recall Experiments
• Serial position
– Where the words are in a list
• Serial position curve
– Chances of recalling words appearing in each position in a list
• Primacy effect
– Remember first 2 or 3 items well (LTM)
• Recency effect
– Remember last few items well (STM)
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Retrieval
• Process of accessing stored information
• Retrieval cues
– Clue or prompt that helps trigger recall of info in LTM
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Retrieving Memories
• Encoding specificity principle
– Ability of a cue to aid retrieval depends on degree to which it taps info that was
encoded at time of original learning
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Context- & State-Dependent Memory
• Context-dependent memory
– Memory can be helped/hindered by similarities/differences between learning context & recall
context
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Context- & State-Dependent Memory
• State-dependent memory
– Memory that is aided/impeded by a person’s internal state
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• Mood congruency effects
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Incomplete Knowledge
• Incomplete knowledge
– Retrieve some features of concept but not enough to identify concept
• Tip-of-the-tongue phenomenon
• Feeling of knowing
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Semantic Network Model
Recall Experiment
Constructing Memories
• Constructive memory
– Use generalized knowledge about world to organize new info as we receive it
– Fill in gaps in info
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Reconstructing Memories
• Memory is actively constructed
– Recall is not an exact replica of original
– Often fit memories to existing beliefs
• Schema:
– mental representations of categories of objects, events, and people
– Useful in forming new memories
– BUT can contribute to memory distortions
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Reconstructing Memories
• Source confusion: Memory distortion that occurs when true source of
memory is forgotten
• False memories: Distorted or inaccurate memory that feels real
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Eyewitness Testimony
• Eyewitnesses can only remember what they perceive
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Eyewitness Testimony
• Limits to accuracy of accounts
– Wording of questions
– Misinformation effect
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Eyewitness Testimony
• Jury’s belief in testimony influenced by:
– How witness presents evidence
– Confidence of witness
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False Memory Research
• “When Memory Lies”
– http://www.pbs.org/saf/1402/video/watchonline.htm
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Forgetting
• Forgetting can be frustrating, but is helpful
– Unimportant information
– Information that was important at one time, but no more
• Forgetting keeps more important info more accessible
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Ebbinghaus
• Method of savings
– Measure of forgetting
– Original learning minus second learning
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Forgetting Curve
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Why Do We Forget?
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Why do we forget?
• Decay
– Gradual disappearance
• Interference
– Presence of some info displaces other info
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Why Do We Forget?
• Retroactive interference
– New info placed in memory interferes with ability to recall info already in memory
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Why Do We Forget?
• Proactive interference
– Info already in memory interferes with ability to remember new info
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Minimizing Retroactive Interference
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Biological Basis Of Memory
• Karl Lashley:
– Taught rats mazes and lesioned different parts of the brain trying to identify the
areas of the brain responsible for memory
– His conclusion was that memories are distributed throughout the brain
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Biological Basis Of Memory
• Donald Hebb:
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Memory is represented by the connections between networks of neurons
His principles are very influential for PDP models
Hebbian learning
What fires together wires together
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Biochemistry Of Memory
• Eric Kandel:
– Demonstration of a process similar to Hebbian learning rule in the actual brain
– Increase in dendritic spines when the two neurons get active at the same time
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Brain Structures And Memory
• Although the memories are stored throughout the brain there are some structures that have critical
impact on memory
– Hippocampus
– Cerebellum
– Thalamus
• New research suggests that these areas are important in the formation of new memories and
avoiding interference
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Hippocampus Damage
• Anterograde amnesia:
– Inability to form new memories
• Retrograde amnesia:
– A loss of memory for events prior to a brain injury
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