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).
