Structure of Long-term Memory Flashcards
Long-Term Memory (LTM)?
The memory systems which store all the experiences and knowledge we gather throughout our lifetime
Information that doesn’t need to be actively maintained, although occasional maintenance helps keep memories stable
Retrospective LTM?
Semantic Memory: Facts
Episodic Memory: Events, mental time travel
Prospective LTM?
The ability to act in the future based on plans made in the past
– “pick up groceries on the way home”
Association between cue and instruction must be strong enough to cause remembering at the right time
- Cues can be internal or external
Researchers divide LTM into two main systems?
Explicit/declarative memory
Implicit memory
Explicit/Declarative Memory? + 2 Subtypes
Includes all memories that we consciously seek to store and retrieve
Semantic:
Retains factual knowledge
Episodic:
Connects the specific times, places and events in an individual’s life
Coding - What is the format of memory?
In STM/working memory, we emphasized auditory, visual, and episodic forms (close to the format it is experienced)
In LTM, exact auditory and visual traces are less precise
- LTM memories are typically further abstracted into meaning and episodic form
Alan Pavio’sDual Coding Theory (1969)? Will be on exam!
Noticed that words that were remembered better were more easy to visualize.
Proposed Dual Coding Theory:
- LTM consists of verbal/linguistic code and imagistic/spatial codes
- Strong memories are represented in both forms
Wickenset al. (1976) coding experiment?
Participants listened to three words, then prevented them from rehearsal (articulatory suppression)
Condition 1, just fruits
Condition 2, fruit, professions, fruit,
Results showed evidence of proactive interference
- Previous information interfered with coding of new semantically-similar information
Results also showed that proactive interference was eliminated when the semantic meaning of the words changed
Conclusion: semantic meaning is important for LTM coding
STM vs. LTM Coding?
STM comprised of visual, auditory, semantic, and episodic traces
LTM codes visually and auditorily too, but much less detail. LTM codes mostly in semantic and episodic form.
In the brain:
– STM/WM actively represented in VLPFC (prefrontal cortex)
– LTM depends on hippocampus
– But both types are widely distributed as well
Classic case study of HM (Henry Molaison)?
HM had both hippocampi removed
- STM was intact
- LTM: no new memories could be stored!
- Anterograde amnesia
Case of Clive Wearing?
Near-full amnesia (retrograde & anterograde) due to brain damage
- STM partially intact
Tulving distinguished between knowing and remembering? Semantic vs. Episodic memory
Knowing:
Being able to say that you have or haven’t seen something before
- Semantic memory
Remembering:
Being able to actually re-experience and reproduce events
- Episodic memory
How to test Knowing? (Semantic memory)
Often tested with a new/old decision paradigm
– Encoding phase: stimuli are presented
– Test phase: prior stimuli are mixed with “lures”, Subjects asked to judge “new” or “old”
Called Recognition Memory
Semanticization of Memory? Petricanet al. (2010) study
Over time, most memories shift from episodic to semantic form
“Remember” responses decreased more than “Know” responses
Semanticizationof remote memories –loss of episodic detail over time
Implicit Memory? + 2 subtypes
To learn without being aware that we are doing so
Mental functions that can be performed automatically in the background
- Procedural
- Priming & Conditioning
