Midterm #2 Flashcards
What does memory do?
Routines and habits. The sense of self. Social functions. Solving problems.
Three stages of memory
Encoding –> Memory Consolidation –> Storage –> Retrieval
Memory encoding
Learning new info, processing info to form a memory, forming new “memory trace” as a neural code.
Memory storage
Retaining encoded memory trace/neural code. Consolidating memory. Takes time.
Memory Retrieval
Activating a memory trace via a cue (probe for that memory) for a purpose.
Encoding a memory in the brain
Encoding: When a memory trace is formed as a hippocampal-cortical activity pattern.
Memory storage in the brain
Consolidation: memory is transformed into a stable cortical pattern.
Memory retrieval in the brain
When a cue (part of a memory trace) triggers pattern completion of the brain pattern.
The multi-store model: Memory as systems
Sensory input –> Sensory memory (information not transferred is lost) –> Short-term memory - rehearsal (Information not transferred is lost) –> Long-term memory –> Short-term memory
Sensory memory
Info that is present in the most unprocessed form. Automatic reflections of a sense. Lasts a very short time. Processed differently in each sense (gustatory, olfactory). Echoic memory, Haptic memory, Iconic memory.
Echoic memory
Brief memory of sounds, help us separate streams of sound quickly. Sound-byte held for around 3 seconds.
Haptic memory
Very brief memory of touch
Iconic memory
Holds visual info for short period, right after you perceive it. Millisecond visual memory. A ‘persistence of vision’.
Iconic memory: Afterimages
Positive afterimage: A visual memory that represents the perceived image in the same colours. Helpful for seeing things smoothly. Exactly what you saw before you looked away.
Negative afterimage: A visual memory is the inverse of the perceived image. Colour is not the same was what you originally perceived, it is the complimentary colours. Slightly longer than the positive afterimage.
Short term memory
Attended information moves from sensory to short term memory. Lasts longer than sensory memory. Also has limited capacity. Prefrontal cortex.
Primacy effect
Remember things you see first (supported by short term and long term).
Recency effect
Remember things you saw most recently (supported only be short term memory).
Chunking strategy
Helps to overcome short term memory limits. Grouping items together in a meaningful way so more information to be represented at one time.
The chunking effect.
Chunking increases with knowledge. Expert chess players recall more pieces on a chess board than new chess players: experts use knowledge of moves to ‘chunk’ prices together. This effect is not present if the pieces are on the board randomly.
Working memory
Retention and manipulation of information not in our environment in conscious awareness. Guides behaviour. Essential for many cognitive functions.
Working memory model
Central executive: moving things around with short term memory stores. Two memory stores: verbal and visual. The phonological loop and the visuospatial sketchpad.
The phonological loop
Store for verbal information
1. Phonological store: Passive store for verbal information Holding onto verbal info. “The inner ear”.
2. Articulatory control loop: Active rehearsal of verbal information. “The inner Voice”. Used to convert written material into sounds (reading).
Visuospatial sketchpad
- The visual cache: information about visual features.
- The inner scribe: Information about spatial location, movement and sequences.
Neuroimaging evidence for short term memory stores
Different areas of the brain are active for visual and verbal short term memory tasks.
Double dissociation in neuropsychological cases: short term memory stores
Patient ELD has problems recalling visual-spatial but not verbal material in the short term. Patient PV has problems recalling verbal but not visual material in the short term.
The episodic buffer
Integrates visual and verbal information. Bridge between short and long term memory. Conscious awareness.
Long-term memory
Implicit: Non-Declarative; Non-Conscious Memory. Procedural and Priming.
Explicit: Declarative; Conscious Memory. Episodic and Semantic.
Encoding Explicit memories
Short term memory –> Encoding (learning) – (Retention Interval Time) –> Memory (recall).
Ebbinghaus
Learned nonsense syllables. tested memory at various intervals, and examined what was retained (forgotten). Used nonsense syllables because they have no meaning. Learned sets of the syllables under strict testing conditions to remove confounds.
The forgetting curve
Memory loss is largest early on and then slows down. Exponential curve that determines how many items you can remember from what you learned.
The spacing effect
Forgetting is reduced when learning is spread over time. Explanation: Repeated information is more valuable. Lesson: don’t cram.
Active rehearsal: The testing effect
Participants studied a text passage. Between group manipulation (studied more; practice test). Both groups took the final test. Retrieving memories after test leads to deeper encoding.
Levels of processing theory
The strength of a memory (and potential for forgetting) depends on processes engaged at encoding. Shallow: Focus on sensory information.
Deep: Integrate higher-level knowledge (things we know) with learned information.
Memory is stronger with deep processing - more elaborate memory traces.
Examples of shallow vs deep processing
Learn new words in a new language, memorizing vocabulary words and their translations is shallow, but using the words in sentences is deep.
Mnemonics using deep processing
Organizational strategies to help encode information. Often involves linking new information to prior (semantic information) knowledge. Chunking strategies. Acronyms to remember lists. Imagery and the Method of Loci: use a familiar image to link encoded info together.
Decay Theory
Memories are lost over time due to disuse. Like a muscle you don’t use, a memory gets weaker.
Interference theory
Interference is responsible for much of forgetting. Encoded memories are labile and need to be consolidated into stable long-term memories. During pre-consolidation period, memories are susceptible to disruption and effects of interfering information.
Proactive interference
‘Forward in time’. Prior information interferes with encoding a new memory. E.g., trouble learning a new phone number because your old number keeps popping up in your memory.
Retroactive interference
‘Backward in time’. Newly learned information overwrites or interferes with a prior encoded memory. E.g., Trouble remembering an older password after you formed a new password. a
Similarity effects
The more alike something is to what is already learned, the more it will mingle and interfere with memory.
The encoding specificity hypothesis
Memory retrieval is better when there is overlap with encoding context. Context can act as a retrieval cue. If you are in the same context that you learn something in when you want to retrieve it, you’re going to remember it better. Context can be internal state or external environment.
Transfer-appropriate processing
Memory depends on the relationship between the information, how it was initially encoded, and then how it is later retrieved. We need to encode info in a manner in which we want to retrieve it later on.
Episodic memory
Specific events and episodes. Retrieve encoding context (what, where and when). Eg., dancing at my high school prom.
Semantic memory
Facts and general information. No retrieval of context of learning. Eg., proms occur at the end of high school.
Children with hippocampal damage
Episodic memory impairment: cannot copy images after a delay.
Semantic memory preservation: normal factual knowledge.
Episodic memory depends on the hippocampus.
Semantic dementia
Relatively spared at episodic memory tasks. Impaired at word naming and picture matching tasks.
Long-term memory 3 consciousness levels
- Anoetic Consciousness: Implicit Memory. No awareness or personal engagement.
- Noetic Consciousness: Semantic Memory. Awareness but not personal engagement.
- Autonoetic Consciousness. Episodic Memory. Awareness AND personal engagement.
Episodic memory: The reappearance hypothesis.
An episodic memory trace is recalled the same way at each retrieval - it is reproduced, not reconstructed. Based on clinical observations that recurrent memories are unchanged from the original event in cases like PTSD.
Flashbulb memories
Vivid memories of significant events that are: Emotionally arousing or shocking events. Retrieve specific details about the time and place when hearing about the event.
Are flashbulb memories special?
Study found that there is a decrease in the number of consistent details for both flashbulb and everyday memories, AND an increase in the number of inconsistent details for both types of memories. Suggests that flashbulb memories are subject to change with retrieval - just like regular memory.
Constructing an episodic memory trace
During retrieval, the hippocampus will bind together whatever details are accessed and activated at that time from the network.
Memory consolidation
Experiences are encoded and then consolidated into a long-term memory trace. The formation of stable cortical representations of memories.
Memory re-consolidation
When a trace becomes activated, it becomes de-stable. Cortical connections can be strengthened and modified during this time, which alters how the memory trace is reconsolidated. Retrieval changes a memory trace.
Impact of constructing memories at retrieval.
Means these memories are susceptible to distortion. We may use general knowledge, semantic memory (schemas) to infer the way things “must have been” in a recalled memory. We may insert false information into the constructed memory, affecting later retrieval.
How does semantic memory affects episodic memory?
Semantic knowledge affects retrieving detailed memories.
How can schemas distort memories
Schemas organize and categorize information, provide expectations about how things should occur.
The War of Ghosts experiments
Participants read an unfamiliar Native American folk story, which did not match Western folk story structure (schema). They examined how the story changed within participants with repeated retrievals. Participants remembered a simplified version of the story and it became more conventional with repeated retrievals. There were omissions and alterations to match Western schema.
False memories
- A familiar feeling can lead to incorrect associations.
- Details can be added to memories during retrieval.
The misattribution effect
Retrieving familiar information from the wrong source (place). A failure in source monitoring (not remembering the where or when accurately).
The misinformation effect
Leading questions can cause false memory formation. Participants viewed a simulated car crash and after were asked: “How fast were the cars going when they contacted each other?” OR “How fast were the cars going when they smashed into each other?”
Implanting memories
Participants recalled childhood experiences recounted by their parents over three experimental sessions. A false memory was added to the list of experiences by the experimenter. 20% of people had a false memory of this event by the end of the third session.
Virtues of reconstructive memory
The same processes that help us construct the past help us imagine the future and plan for our lives. These are processes of the hippocampal episodic memory system.
The Rashomon Effect
Memories are reconstructions… Is this why people can recall the same event differently?
Implicit memory: Procedural memory
Automatic behaviour/actions. Patterns of movements encoded in the brain: Basal Ganglia - motor sequence. Prefrontal cortex - organization. More immune to forgetting compared to other types of memory.
Habits: when deliberate actions become routine
Initially rely on explicit memory; with training and or exposure will then rely on implicit memory. Motor action sequences, repetitive thoughts or emotions, basis of some addictions.
Habit formation
Prefrontal cortex is important for keeping habits going. Rats were trained on a T-shaped maze with tones to signal reward at the left or right end. Required the stratium.
Breaking habits
Removing a reward at one end, or making one reward gross (non-rewarding) did not break the habit of the rats. To break habit, need to inhibit prefrontal cortex, which is the region that monitors habit.
Implicit memory: Priming
Prior exposure facilitates information processing without awareness. Example: Word-fragment completion test. Participants are shown a list of words. Asked to complete word fragments. Participants are likely to use prior words to complete the fragments without knowing it.
Implicit emotional responses
Automatic emotional response to scary/emotional: fear response to snakes, the dark and other scary stimuli. Amygdala is important for both implicit and explicit emotional memory. Conditioned emotional response is important for things that could harm us.
Explicit memory
Semantic: facts
Episodic: unique episode/experience
Everything starts off as episodic memory in some way. Key difference: episodic memory is about one key episode, semantic is about general knowledge.
Semantic memory organization
Goes from general to specific.
Unit: concept
Properties: feature or description of unit
Pointers: depicting relationship between concepts and properties
Spreading activation in the semantic network
When you retrieve one concept, that activity will spread to other closely related concepts. Semantic priming: related ideas triggered at retrieval. Trains of thought that might seem nonsensical.
Dissociations in longer term memory: Amnesia due to brain injury
HM: Experimental neurosurgery to reduce seizure activity. Bilateral medial temporal lobe, including the hippocampus removed. Selective episodic memory loss.
HM and the role of the hippocampus in episodic memory
Intact short-term memory: can remember a short list of words for 30 seconds. Intact procedural memory: could learn new skill-based tasks. Intact semantic memory: could recall major historic events of childhood. Profound episodic memory loss: could not learn new information and recalled his past in sparse detail.
Anterograde amnesia
This is the inability to form new episodic memories. Info cannot move from short term to long term.
Retrograde amnesia
The loss of memories form before the onset of amnesia. Specific to episodic memory. Temporally graded: memories closer to event (more recent) will be more affected.
Dissociative amnesia
Results without any brain injury at all - a very rare psychiatric disorder. Related to information about the self. Leads to shifts in lifestyle. Usually a response to psychological and physical trauma.
Dreams and amnesia
Dreams are linked to memory - Theory: dreaming helps people process past experiences as they sleep. Patients with focal bilateral hippocampal damage and amnesia and healthy controls. Woken up at various points during thenight and asked if they dreamt and to describe the dreams. People with hippocampal damage reported fewer dreams and the dreams they had were much less detailed. Experiment suggest perhaps you need functioning memory process to engage in dreams.
Dementia: pathological aging
Umbrella term. Dementia: progressive cognitive and functional impairments due to neuronal death. Alzheimer’s: starts with episodic memory.
