Unit 8: Memory (Chapter 7) Flashcards
The case of H.M.
Case study of a man who had large part of his hippocampus removed in attempt to alleviate his seizures → hit by a cyclist as a child. This lead to a severe form of anterograde amnesia (the inability to form new memories).
Memory
The capacity to store and retrieve knowledge.
• Adaptive value: allows animals to use information from the past to respond quickly to new challenges and to navigate our environment (i.e. where food/ predators are).
What are the three stages of memory?
- Encoding
- Storage
- Retrieval
Encoding
Process of acquiring information and transferring it into memory.
Storage
The retention of information for later access. Can last from fraction of a second to an entire lifetime.
Retrieval
The recovery of stored information. What we retrieve is not identical to what was stored.
Multistore model of memory
Model proposing that sensory information flows through three stores differing in capacity and duration:
- Sensory memory
- Short-term memory
- Long-term memory
Sensory memory
- Capacity: very large
- Duration: very brief, < 1 sec (just long enough to process)
- Sense specific (e.g., visual, auditory): iconic and echoic memories
- Purpose may be to collect imaging data long enough to determine what is worth processing
Iconic memories
Sensory memory for visual information. Lasts less long than echoic memories.
Echoic memories
Sensory memory for auditory information (see after-image of lightning, sparklers). Last slightly longer than iconic memories (might have to do with processing since auditary stimuli are transient).
Short-term memory
Second stage of multistore model of memory.
• Duration: brief (seconds to a minute)
• Capacity: small
• Classic estimate: 7 plus or minus 2 items → why phone #s in NA are 7 digit.
- Variability, may be closer to 4
Chunking
Process of grouping similar or meaningful information together.
Ex: Which is easier to remember?
ODGACTIBORSIFHRBIBTA or DOGCATBIRDFISHRABBIT
Research example: Chess masters can recall placement of chess pieces better than non-players (but only for piece placement from real games); use chess knowledge to chunk pieces’ placements!
Working memory
Extension of the concept of short-term memory that includes active manipulation of multiple types of information simultaneously.
Stemmed from the fact that people could read a set of #s and then a paragraph; if only short-term memory they should be overwhelmed!
Phonological loop
Working memory component responsible for verbal & auditory information.
Rehearsal
The act of repeating information to keep it in short-term memory → using voice in head.
Visuo-spatial sketchpad
Holds visual & spatial information (mind’s eye).
Central executive
“The boss”. Memory component that directs the other components by directing attention to particular tasks.
• Bidirectional relationship b/w short-term & long-term memory
• Can draw on information stored in long-term memory to perform manipulations like chunking
Long-term memory
Storage level of memory where information can be held for hours to many years and potentially a lifetime.
- No clearly defined limits in capacity or duration
- Evidence of dissociation between short-term and long-term memory in serial position curve/effect (recency and primacy effect) and neuropsychological studies (anterograde and retrograde amnesia).
Serial position effect
Recall varies as a function of position within a study list (better remembering the first and last words than those in the middle).
Graph forms sort of a smiley face like a creepy serial killer.
Primacy effect
Better recall for items at the beginning of the list. Due to more rehearsal → storage in long-term memory.
Recency effect
Better recall for items at the end of the list. Due to availability of these items in short-term memory or working memory. Disrupted if recall is delayed.
Amnesia
Loss of memory due to brain damage or trauma. Short-term memory is usually preserved.
E.g. H.M. Could do tasks like hold a phone number in short-term memory. He showed a reduced primacy effect but a normal recency effect.
Anterograde amnesia
Unable to form new long-term memories.
No new memories going forward (think anter = after).
Retrograde amnesia
Unable to access memories predating brain damage, but able to store new memories in long-term memories.
No recollection of old memories (think retro = going back in time, no memory then).
Levels of processing theory
Encoding is an active process that can occur at multiple levels ranging from shallow to deep. Deep encoding leads to better memory performance.
Shallow encoding
Encoding based on sensory characteristics, such as how something looks or sounds.
- Maps onto basic brain regions related to perception of sensory information (visual or auditory encoding; occipital + temporal lobes)
Deep encoding
Involves making associations between new information and old information already stored in your brain (elaboration).
• Thinking about the meaning of the word (semantics)
• Drawing connections to other things you already know
Engages higher-order brain regions related to thought (e.g., frontal lobes, temporal lobe regions related to semantic information). Also associated with increased activity in the hippocampus.
Self-referential encoding
Type of deep processing where information is related to oneself. Enhances memory retention, as humans love to think/talk about themselves.
Different forms of long-term memory
H. M. could not form new memories of people he had met, conversations he’d had, things he had done - anterograde amnesia.
• But could learn new challenging skill → Ex: shown a figure and traced its outline using a mirror.
• Suggests that there may be different forms of long-term memories, only some of which are reliant on the hippocampus.
Types of long-term memory
- Explicit/declarative
- Implicit/nondeclarative
Explicit/declarative long-term memory
Intentional, conscious.
Implicit/nondeclarative long-term memory
Occurs without intentional recollection or awareness, measured indirectly by observing effect of prior learning on behaviour. Difficult to verbalize (like trying to explain to someone how to ride a bike).
Procedural memory
Type of implicit memory related to the acquisition of skills (e.g., riding a bike, using scissors, knitting, or drawing a five-pointed star in the mirror).
- When procedural skills become automatic, can direct our attention elsewhere.
- H.M. could learn new skills but could not remember learning them in the first place
Ex: Driving, using scissors.
Priming
Change in response to a stimulus as a result of exposure to a previous stimulus.
- Priming is observed in patients with amnesia, demonstrating that implicit memory is intact.
- Not reliant on hippocampus or deeper processing
Affective conditioning
Type of classical conditioning where a neutral stimulus becomes associated an emotionally charged stimulus, leading to a conditioned emotional response. Ex: Recall “Little Albert” study.
• Affective conditioning is preserved in amnesic patients. Ex: Neurologist pricking patient’s hand, patient not wanting to shake his hand the next day, but was could not remember why.
• Does not rely on hippocampus: Individuals with hippocampal lesions still exhibit fear conditioning in lab studies (operationalized as increased galvanic skin response, “sweating”, in response to cue previously associated with blast of noise).
Episodic memory
Remembering Hippocampus is your personal “time machine”, which allows you to travel back in time (retrospective memory) through episodic memory → memory of yourself experiencing the event.
• Explicit recollection of personal experiences.
• Impaired in amnesia. E.g., HM unable to form new episodic memories.
Prospective memory
Hippocampus also allows travel to the future.
• Prospective memory = memory for things we need to do in the future
• Also impaired in individuals with retrospective memory loss
Semantic memory
Knowing Explicit memory reflecting knowledge about the world, including concepts and facts. Does not rely on hippocampus. Mediated by surrounding parts of temporal lobe.
E.g. you being able to explain how neuronal signaling works or knowing that; knowing random animal facts.
Hebbian learning
Neurons that fire together, wire together.
Long-term memories are made & consolidated at the cellular level: neurons contain remnants of past communication (memory traces). When two neurons are active at the same time, the connection between them becomes stronger. This strengthening of the connection makes it easier for them to activate each other in the future (long-term potentiation).
Consolidation
The process through which a memory trace is stabilized and strengthened following its initial acquisition.
• Time-dependent biological processes
• May be disrupted by: Presentation of new information presented shortly afterwards, head injury, electroconvulsive therapy (ECT).
• Does not require conscious effort (sleep leads to stronger memory consolidation)
Spreading activation model of memory
Memory is organized in associative networks where nodes (concepts) are linked together (associations).
• Concepts become associated if:
- They have co-occurred repeatedly.
- They share properties in common.
- When one node is activated, related nodes become primed & are more easily retrievable.
Retrieval cue
Stimulus or thought that primes a particular memory. Elaboration helps create more connections, and thus more retrieval cues.
Trace decay theory of forgetting
“Use it or loose it.” If memories are not accessed, memory trace will fade over time.
• Ebbinghaus forgetting curve: Memory retention drops sharply without further reinforcement, and repeated retrieval practice slows down forgetting
Interference theory of forgetting
Forgetting occurs because memories interfere with and disrupt each other. Interference is more likely to occur when tasks at hand are similar but conflicting.
Two main types of interference include:
- Retroactive interference
- Proactive interference
BUT prior learning can also be helpful due to positive transfer.
Retroactive interference
The disruptive effect of new learning on the recall of old information.
Proactive interference
The disruptive effect of prior learning on the recall of new information.
Ex: Learning a new language later in life.
Positive transfer
Learning acquired in one context enhances performance or learning in another context.
Ex: verbs in French and Spanish.
Role of CREB in memory consolidation
The cAMP response element-binding protein (CREB) is a transcription factor that plays a central role in long-term potentiation (LTP) and memory formation. Gain of CREB function improves memory consolidation and LTP, while loss of CREB function impairs memory consolidation and LTP.
Recognition
A form of retrieval that relies on identifying previously seen or experienced information.
Example: Multiple-choice tests with answer options provide retrieval cues.
Encoding specificity principle
Retrieval works best when it recreates the way the information was initially encoded.
On-land vs underwater learning and retrieval study.
Mood-dependant retrieval
The increased likelihood of remembering when a person is in the same mood during both encoding and retrieval.
• People in a sad mood are more likely to retrieve sad memories
• People in a happy mood are more likely to retrieve happy memories
Encoding failures
Information never makes it into long-term memory.
- May occur because we did not attend to it (e.g multitasking).
- Weapon focus effect.
Weapon focus effect
Witness’s attention is drawn to a weapon during a crime, which impairs ability to remember other details of the event.
- Witness’ memory is likely focused on weapon
- Limitation to eyewitness testimony
Free recall
Information is accessed without any cues to aid retrieval.
Free recall is different from cued recall, where participants are given cues or hints to help them remember the items. Free recall is also different from serial recall, which is the ability to recall items in the order they occurred.
Are emotional memories more likely to be remembered?
From an evolutionary perspective, adaptive to remember emotion-laden events.
• Study example emotionally arousal video presented immediately after lecture enhances memory for lecture material.
Caveats:
• Timing matters: stress may either impair or enhance memory for an event depending on timing. Effect works best when the emotional arousal happens around the same time as the event/ simultaneously.
• Chronic (ongoing) stress has deleterious effects for memory!!!
Potential underlying mechanisms:
• Brain activity is enhanced for emotional events in the amygdala and hippocampus.
• Amygdala facilitates the consolidation of long-term memories made by the hippocampus
• Stress hormones promote attention and encoding efficiency. Administration of an stress-hormone blocker (propranolol) reverses memory advantage for emotional events.
• Individuals with no amygdala have more long term memory for neutral events.
Flashbulb memory
Especially vivid & detailed memory of an emotional event. Associated with more confidence but not necessarily more accuracy.
Memory reconsolidation
Process wherein previously consolidated memories are recalled & stored again for long-term retention.
• Renders memories malleable & susceptible to modification
• Common misconception that memory is like camera recording
• In the words of renowned memory researcher Elizabeth Loftus, memory is more like a Wikipedia page, subject to revisions both by oneself and others
Loftus & Palmer car accident study, which suggested words like “smashed” versus “hit” and asked Ps at what speed the was car going. Also brought them back to the lab later, and asked if there was any broken glass.
Misinformation effect
Additional information received after an event is later mistakenly recalled as part of the original event. Suggests that memory can easily be distorted. Some real-life implications:
- Eyewitness testimony → controversial!
- Recovered memories
- Played a role in the “Satanic Panic” of 1980s
- In the Loftus & Palmer (1974) study, the leading question is the “misinformation”
- Ex: Ps shown 2 real events and one fake event, 25% elaborated, added details to event. Larger replication where mock jurors believed a false memory.
False memories
- Not as rich or vivid
- Less willing to testify when asked
- Ps more likely to identify fake story when informed of the purpose of the study
Generalizability?
• Emotional significance of the event → lost at the mall does not equal abusive experiences
• Commonplace vs. rare events
• Familial informant vs. therapeutic setting
• Successful implantation of memories of less common and/or emotionally charged childhood experiences-e.g.:
• Taking a hot air balloon bride
• Spilling punch on a bride
• Being attacked by an animal
- Increased belief that they experienced implausible events (e.g., witnessing demonic possession). I.e. less convinced that this did not 100% happen to them.
Source amnesia
Occurs when cannot identify the provenance of our memory.
Source monitoring
Ability to recall the context in which we acquired a memory.
Error of source monitoring
E.g., when we cannot remember whether we saw something in a news article or Facebook newsfeed.
Error of reality monitoring
When we forget whether we actually experienced an event or merely imagined it.
Imagination inflation
Imagining an event that never happened increases confidence that it actually occurred.
The more interviews, and the more time spent imagining the planted event, the more confidence Ps had that it actually happened.
Gist memory
The general global aspects of the supposed event.
• Gist memories are highly durable and long tasting → might outlast a real memory!
• Cannot judge veracity of memory by its persistence
• Mind fills in the gaps (missing or forgotten details) by using the gist, which can lead to inaccuracies!
Verbatim memory
The specific details of an event.
Deese-Roediger-McDermott (RDM) paradigm
Two lists of words read out loud. Most likely to say words were named in the second list after a delay if they were related to the theme of the original list of words.
State-depending retrieval
The increased likelihood of remembering when a person is in the same mental state during both encoding and retrieval.
Ex: Remembering a memory formed during a stressful time while under stress.
Source memory
Recalling the context of learned information, such as knowledge of when or where something was learned.
What does it mean for memory to be constructive?
What you recall from your memory isn’t always actually what happened; memory can be altered or erroneous. Memory is rebuilt, and may easily be influenced. Showcased through false memory studies. Ex: Loftus and Palmer car speed video study.
Neural persistence
Continued activity in neurons after a stimulus ceases, which rapidly fades.
Working memory span
Measured by how many items can be juggled and manipulated in the mind using simple span tasks (increasing the number of items in a list to remember).
Long-term potentiation (LTP)
An enduring (long-term) enhanced (potentiation) form of communication between neurons.
- LTP increases the amount of CREB (cAMP-response element binding) protein, which might represent the molecular basis of memory. CREB is able to interact with genes in neurons, which can increase the neuron’s response to stimulation. Spaced learning is associated with increased CREB expression.
Free recall
Recall from memory isn’t accompanied by retrieval cues or hints.
Negative transfer
The detrimental effect of your past memories on how well you can learn and perform today.
Tip-of-the-tongue phenomenon
A failure to retrieve information, often the name of a person or place, though we are confident it is stored in memory. Occurs increasingly with age.
Motivated forgetting
Occurs when individuals intentionally try to forget information so that they are less likely to retrieve it later.
Infantile amnesia
The inability of adults to retrieve episodic memories from the first few years of life, usually from birth to age 3-3.5 years old.
Reminiscence bump
A time of prominent memory making between adolescence and early adulthood.
Spacing effect
Information is better remembered when encoding is spaced over time.
