Test #2 Flashcards
Pattern Separation
process that parses similar events into
more distinct, non-overlapping representations
Pattern completion (PC):
process that interacts with partial
information to reconstruct a complete event
The MTL Memory System
The MTL memory system includes the hippocampal formation (CA fields, dentate gyrus, subicular complex), perirhinal, entorhinal, and parahippocampal cortices.
Episodic encoding and binding in MTL
MTL believed to be responsible for binding features into an
integrated memory trace
• receives highly processed input from many brain areas
when an event is encoded
• MTL then binds together input at encoding
Content Addressable Memory
ANy aspect of the content of memory can serve as a reminder that could access the experience
retrieval cue often consists
of some of the input processed at encoding.
processed retrieval cue converges on MTL, triggers pattern
completion within the hippocampus, which in turn
reactivates information in neocortex
Encoding
At encoding—an event is processed by regions associated with different features of event; processed information converges at hippocampus and features are bound
Retrieval
At retrieval-- cue processed by regions associated with features of cue, and then converges to hippocampus; if retrieval successful, cue then connects with memory trace and projects to regions associated with memory
Describe the Episodic Retrieval Process
episodic retrieval: processes by which stored memory
traces are retrieved
• assumed that retrieval produces subjective experience of
consciously remembering the past
• episodic retrieval is assumed to depend on hippocampal
regions that support pattern completion and frontal lobes
that support strategic retrieval – thus, there are multiple ways in which a retrieval cue
can access memory trace, and partial information may
be enough to access memory trace
Hippocampus is activated during successful retrieval but not unsuccessful.
What are some retrieval tasks
Brewer et al., 1998
• Indoor/outdoor judgments to complex scenes during eventrelated fMRI
• Subsequent memory test 30 min. after scanning (new vs. old) – Remember (distinct recollection of having seen photo) vs.
know (feeling of familiarity) vs. forgotten
Recall of public events
What is the tip-of-the-tongue phenomenon
an extreme form of pause where the word takes a noticeable time to come out - although the speaker has a distinct feeling that he/she knows exactly what he/she wants to say.
Retrieval (Textbook)
The process of recovering a target memory based on one or more cues, via associative connections linking them together subsequently through a process of spreading activation, bringing that target into awareness.
Target Memory or Trace
A particular fact, idea or experience
Associations or Links
Traces in memory are believed to be linked up to one another by connections. Example; Fruit/banana.
Spreading Activation (Retrieval)
Each memory has an internal state of its own, reflecting how excited or active it is, a state referred to as the memories activation level.
Memories spread activation to other memories to which they are associated.
Activation Level
The variable internal state of a memory trace that contributes to its accessibility at a given point.
Cortical Reinstatement
neural activity of a trace memory that was present at that experience reactivates in the various regions of the brain associated with the properties of that memory.
What are the factors determining Retrieval Success
1) Attention to Cues - Diminishing attention may make a cue less useful
2) Relevance of Cues - Must be related to target
3) Cue-Target Strength - Retrieval success depends on how associated the cues are to the target, which depends on the time and attention we spend encoding the association.
4) Number of Cues - Retrieval often improves when more relevant cues are added.
5) Strength of Target Memory - If a memory is weakly encoded, even a good cue may be insufficient to trigger retrieval.
6) Retrieval Strategy - Retrieval can be influenced by the strategy one adopts.
7) Retrieval Mode - The cognitive set, or frame, of mind, that orients a person towards the act of retrieval, ensuring that stimuli are interpreted as retrieval.
Encoding Specificity Principle
The more similar the cues available at retrieval are to the conditions present at encoding, the more effective cues will be.
Context Cues
Retrieval cues that specify aspects of the condition under which a desired target was encoded, including, for example, the time and location of an event.
Direct/Explicit Memory Tests
Any of a variety of memory assessments that overtly prompt participants. Recalling the past requires context as a cue.
Free Recall: Necessitates the use of strategies for generating answers in some order.
Cued Recall: Requires context as a cue but context is ss supplemented with specific information that focuses search. Easier then free recall and doesn’t rely heavily on retrieval strategies.
Recognition Test: Easiest type of direct test that simply requires making a decision.
Indirect Memory Tests
Measure the influence of experience without asking the person to recall the past.
Recognition Memory
A person’s ability to correctly decide whether he/she has encountered a stimulus previously in a particular context.
Signal Detection Theory
- A model of recognition memory
- Memory targets have signals and noises on a recognition test
- Possess attribute known as strength or familiarity
- occurs in graded fashion
- Provides analytic tools that separate true memory from judgment
Dual-process theories of recognition
A class of recognition models that assumes that recognition memory judgments can be based on two independent forms of retrieval process: recollection and familiarity.
Familiarity Based Recognition
A fast, automatic recognition process based on the perception of a memory’s strength. Proponents of dual-process models consider familiarity to be independent of the contextual information characteristic of recollection.
Remember/Know Procedure
A procedure used on recognition memory tests to separate the influences of familiarity and recollection on recognition performance. For each test item, participants report whether it is recognized because the person can recollect contextual details of seeing the item (classified as a remember response) or because the item seems familiar, in the absence of specific recollections (know response).
Process Dissociation Procedure (PDP)
A technique for parceling out contributions of recollection and familiarity within a recognition task.
Source Monitoring
The process of examining the contextual origins of memory in order to determine whether it was encoded from a particular source.
Is interference effect from DA at retrieval material- or process-specific?
free recall is disrupted by competition for phonological or word-form representations during retrieval • equally resource-demanding picture-based distracting task produced significant interference with memory retrieval, but the effect was significantly smaller in magnitude
Recollection vs. Familiarity
Familiarity is faster • Operate in parallel • Independent • Familiarity is strength-based; Recollection is a threshold (context) • Familiarity = more automatic Recollection = controlled and effortful
Recollection vs. Familiarity
• specific, detailed vs. vague feeling of “pastness”
• controlled vs. automatic
• Tulving: episodic memory gives rise to recollection
(‘remembering’), whereas semantic gives rise to familiarity (‘feeling
of knowing’)
Remember/Know Paradigm
• ‘remember’ response if specific instance of study can be called to
mind
• ‘know’ response if item is known to have been studied but a
specific memory was not formed
Reminiscence Bump
Enhanced memory for (episodic and semantic) facts
of adolescence & young adulthood
Semantic Memory Vs. Episodic Memory
Semantic Memory is general knowledge about the world whereas Episodic Memory is a recollection of the past. including events with time and place.
Semantic Memory is free of context and it does not matter where you learn the information whereas Episodic memory includes the context of the information recalled which is richer in detail.
Example Coffee Shop
Remembering where the coffee shop was and what time you went (Episodic) whereas (Semantic) involves general knowledge about coffee shops, what coffee tastes like and so on.
Semantic Organization
External forces that determine how we categorize things. We tend to naturally categorize things in our world in order to make sense of them.
Semantic Dementia
Relatively intact episodic memory but severe problems with semantic memory. A progressive neurodegenerative disorder characterized by gradual deterioration of semantic memory.
Internally Driven Categorization
Rosch and others argued that the way we categorize the world is internally driven and not driven by external factors and certain aspects of the way we categorize the world are independent of language.
Concept
A specific category membership and they are related to one another based on some common meaning. It is based on our semantic and mental representations that determine how things are categorized.
Cognitive Economy
The idea that Semantic memory is organized in a way that avoids excessive duplication
Basic Level of Categorization
Default level at which we categorize; basic level of representation for a thing at its most basic level.
Lexical Decision
Having participants make a lexical decision between words and measure accuracy and reaction time.
Category Decision
Is trout a fish? Measure accuracy and reaction time.
Similarity Judgement
How similar are two things?
Semantic Network
Thinking about semantic representations in terms of concepts and their relation to others in a network of pathways in the semantic memory system.
Node
A point or location in semantic space that corresponds to a concept or a simple fact about a concept which are connected by neural pathways in semantic memory.
Node Activation
The node related to a concept is said to be firing or active.
Collins and Quiggins Hierarchical Model
Concepts are organized in a hierarchy that implements the cognitive economy and is connected by nodes. There is a hierarchical link best characterized by “IS A” to describe the relationship between a lower-order concept and a higher-order one.
Information is stored as high as possible to minimize the amount of information needing to be stored in semantic memory.
Sentence Verification Tasks
How fast a participant can respond indicates the relationship between nodes and if they are close or long.
A way to test the model.
Difficulties with the Hierarchical Model
The Prototypicality Effect: The finding that the time taken to decide a category member belongs to a category is less for typical than atypical members.
- Mistaken in assuming that concepts belong to rigidly defined categories.
Relatedness Effect ; Things may be equally untrue because of the semantic relatedness; A pine is a chair vs a pine is a flower. They are both false however they might be related in some sense.
Spreading Activation Model
- Designed to resolve problems with Hierarchical model
- Semantic memory is organized through relatedness or semantic distance
- Activation occurs when you think about a concept which spreads most strongly to other concepts that are related semantically.
Problems
- Flexibility makes it difficult to make precise predictions
- difficult to assess overall adequacy
- Information isnt distributed in a single node but rathera cross different regions
- Model implies a fised representation but our idea of concepts is flexible.
Smiths Feature Overlap Model
Knowledge is stored in terms of feature overlap, not hierarchies, semantic features
The meaning of a word or concept is decoded into its decomposition into smaller units instead of a position in a network of a meaning.
Individual concepts are sets of features and concepts are similar if they share features.
Boundary between concepts is more graded and te relationship between them is mode graded.
Two Routes for making Category Decisions
Fast Route; A global comparison of features based on the overlap of features that can be quickly assessed.
Slow Route; Requires you to look up features or defining features for a category. A bat is not a bird = flight
Difficulties with this Model
1) Some categories do not have any obvious features that are all common to all members (games and game)
2) Cognitive Economy; in this model, it is full of redundancies and typically represents features that are common against multiple concepts.
Situated Simulation Theory
- Conceptual knowledge involves perceptual and motor systems.
- The Precise way we process a concept depends on the situation and the perceptual and motor processes engaged by the current task.
Limitations
- Concepts possess a stable abstract core that has yet to be disproven
- perceptual and motor features/context processes may occur only after concept meaning has been accessed.
Schemas
Organizational Structures that allow us to make sense of our world. Fitting new knowledge into existing structures representing some aspect of the environment, our experiences or beliefs.
Scripts
a sequence of actions that occur or something that defines a scenario; a sequence of events (having a meal at a restaurant).
Category Specific Deficits
Disorders caused by brain damage in which semantic memory is disrupted for certain semantic categories.
Domain-Specific Deficits
Living things vs nonliving things.
Hub and Spoke Model
- The Spokes consist of several modality-specific brain areas in which sensory and motor processing occur
- Each concept has a hub - a modality independent unified conceptual representation that provides an efficient way of integrating our knowledge.
Frames
A type of schema in which information about objects and their properties is stored.
Perceptual vs Functional Theory
Conceptual knowledge organized in brain through modality
Perceptual Features: usually visual, color, shape
Functional Features: what it is used for, what can it do
Living things tend to be based on perceptual features and nonliving things tend to be based on functional features.
Allports Model of Semantics
Features an object represented across various domains (tactile, visual, auditory )
- When you retrieve an object, its features are coactivated
- Certain features rely on other features than others
- Might rely heavily on domain (eg; perceptual)
- its activation may be sufficient to fully reinstate object but damage could impede other domains.
Difficulties with this Theory:
Cannot account for category-specific deficits following widespread damage.
Perceptual and functional features not equated for difficulty; harder to make judgements about perceptual feautres
Evidence that category-specific deficits are not modality-specific (deficits for all features of the impaired category)
PET of Category disassociations
participants were presented with different types of objects; possible and impossible; cared about activity associated with the possible; wanted to substract out the perceptual processing in order to see what parts of the brain are uniquely activated; perhaps will say something of where the concepts are placed.
OUCH: Organized Unitary Content Hypothesis
“provide evidence or describe a theory that is used to explain category specific deficits”
Feature correlations: the main idea is that certain features tend to cluster together across similar concepts (eg; things that also tend to and to
Members of superordinate category share many features
- Some regions of "semantic space" will be more densely populated (concepts with many correlated features) than other regions (concepts with few correlated features) Focal damage will result in specific deficits for categories whose members contain features represented in damaged region.
Evidence that supports OUCH
Accurately predicts that category-specific deficits will not also be modality-specific.
Able to account for violations of the living/nonliving distinction
- Damage may affect multiple clusters of features
Able to account for narrow category specific deficits
Eg; fruits will be selectively impaired if the relevant cluster of
Shortcomings of OUCH: Does not not explain why living things are much more likely to be impaired than nonliving things; why are some feature clusters more likely to be impaired,
Difficult to Falsify: can account for any pattern of category-specific deficits
Differential Distribution of Feature Correlations: Why are living things more vulnerable to category-specific damage?
Living things more likely to cohere around clusters of intercorrelated features than nonliving things.
- Feature correlations more plentiful and stronger in living things
Living things also tend to have fewer distinguishing features (ie; features that occur in only one or a few concepts)
Brain damaged patients will have difficulty distinguishing between concepts that have relatively few distinguishing features
More interrelated features versus distinct features
Minimal Brain Damage; unlikely to get rid of the concept of all living things buta critial point where you can lose the entire concept called Catastrophic Loss: all concepts that contain the same cluster of features will be lost; this results n the loss of the entire category.
Predictions for Category-specific deficits in AD Patients: loss of nonliving concepts linearly related to amount of the damage that has occured and living things concepts should show initial insulation in very early stages of AD
In later stage should see loss of entire categories because shared cluster of features can no longer be activated
Critical to examine individual patients separately.
Confabulation
An unintentional, spontaneous or provoked inconsistent account that serves no purpose where the patient is completely unaware of distortions.
- Deficit in Strategic Retrieval
- Impaired ability to withhold response or monitor what is given
Confabulation Temporal Account
- Tendency to confuse time at which the information was encountered.
- observations can be based on fragments of real experiences
- Failure to represent new information so old information intrudes on present thinking
- failure to suppress the memories that appear in association with reality.
- Continuous recognition showed that patient old information intruded on present thinking.
Confabulation Strategic Retrieval Account
- Difficulty lies in strategic search process when cue not readily available , particularly when monitoring outcome of search.
- General difficulty in memory specification and monitoring
- Distortion of true details
- details from another story
- idiosyncratic incorportation
- high amount of confidence regardless of accuracy
Remote (Retrograde) Memory
Recent memories are usually semantic and then move into episodic (remote)
Anterograde Amnesia
Unable to form new explicit memories
Retrograde Amnesia
Unable to obtain memories shortly before accident
Testing Remote Memory Amnesia
Famous Faces Test
Public Events Test
Autobiographical Test
Results
-Hippocampus appears to play temporary time limited role in declarative memory
Consolidation Theory
All memories initially dependent on hippocampus but gradually become established in neocortex.
- Spared remote memory with patients with hippocampal damage
- memory vulnerable to disruption consolidation complete, so recent memory worse than remote
- Unable to account for all types of remote memory.
K.C Case Study
- Preserved remote semantic memory
- Impaired episodic memory for all times in his life
Hippocampus and Episodic Memory
Hippocampal damage leads to severe and extensive episodic memory impairment.
Multiple Trace Theory
Hippocammpus and Neocortex represent autobipgraphical episodic memories for a lifespan
- each time a memory is retrieved, a new memory trace is created
- memory becomes more resistant to partial lesions
Autobiographical Memory
Memory across the lifespan for both specific events and self-related information.
- Recent memories are more episodic
- More vivid and detail then remote
- Repeated events tend to be less episodic and more semantic
- Both episodic and semantic
- Self referential
Conway Model of Autobiographical memory
-Highest level of hierarchy are themes or important life goals
