W4) 8) Human Memory Systems Flashcards
What is memory?
Definition – The ability to store and retrieve information over time
There are multiple different types of memory and evidence suggests these different types are stored differently in the brain
What are the different types of memory?
What are the different types of memory?
Iconic memory - lasts under a second. Eg. We put pressure on our hand, we will feel it a fraction of a second after we let go.
Short term memory - Information held for less than 30 seconds. +/- 7 item capacity. Need to do subvocal rehersals. This is when you need to keep saying it inside your head to remember a phone number for example.
Working memory - the small amount of information that can be held in an especially accessible state and used in cognitive tasks
Intermediate term memory - This is between the short and long term memory. 30 seconds to about 2 weeks. Eg. Finding car in a car park.
Long term memory - Theoretically it is permanent.
Episodic memory (autobiographical) - Situations or events involving yourself.
Semantic memory - This is facts about the world. Anatomically different spaces.
Declarative - This is information you know you know, but you might not always be able to access it.
Procedural- How do to action. Eg. How to ride a bike, play chess.
Prospective - Memory of the future intentions. 30 intentions at any one time. You can’t subvocally do that - this is unconscious.
Damage to one system is one loss, damage to another system is another loss = double dissociation.
What is the critical concepts in neuropsychology?
Dissociation and double dissociation
Help to identify neural substrates of various brain functions
Dissociation = When you know localisation of brain damage or lesion and find that one function is knocked out but other related functions are preserved e.g. individual looses ability to name category of animals but can name all other objects.
Double dissociation = Lesion in specific brain area impairs function x but not y then demonstrate that lesion of separate brain area impairs y but not x.
Patternson & Plaut “the gold standard was always a double dissociaation” 2009
What are the key processes in memory?
There are three key processes in memory:
Encoding
Processes occurring during initial encounter with to be remembered stimulus = stage 1
Storage
storage in the memory system = stage 2
Retrieval
recovering stored information from the memory system = stage 3
Forgetting can result from failure of any of these stages, rather than a process in itself.
Consolidation = working memory to long term memory.
What is the memory structure?
Looking stuff up on Google, using satnavs makes our brains worse…
See if you can figure it out for 2 mins before Googling to not lose function.
What are the sensory memories?
Auditory [Echoic] Memory
Holds information for approx. 3 seconds
Visual [Iconic] Memory
Holds information for approx. 250 ms
What is short term memory?
STM – now termed Working Memory (Baddeley & Hitch, 1974)
This consists of three components:
Central Executive: this resembles what we would call ‘attention’
Phonological Loop: holds information in a speech-based form
Visuo-Spatial Sketchpad: specialised for holding visual and spatial information
What is working memory?
WM is a much more dynamic store than a unitary STM
Working memory has a limited capacity (LTM is theoretically without limit, in both capacity and duration of storage)
It is usually found that we can only store around 7 ± 2 pieces of information in memory (Miller, 1956)
But beware of chunking – grouping bits of information to make remembering easier.
What is double dissociation in memory?
Are short term memory and long term memory distinct?
If they are we would presumably see patients with impaired STM and preserved LTM? If we also saw the reverse pattern preserved STM and impaired LTM this would be an example of a double dissociation.
Researchers and clinicians have found this pattern to be supported.
E.G. KF = patient with impaired STM but fine LTM (Shallice & Warrington, 1970)
What is interference in memory recall?
Interference in WM
Traces only remain in WM with repeated rehearsal (i.e. attending to the information)
They are therefore prone to interference
Retroactive interference:
New information interferes with the retention of old information in WM (trying to remember your old phone number, having used your new number for a few months; finding it difficult to revert back to manual gear changes having recently been shown how to use an automatic)
Proactive interference:
Old information interferes with the recall of new information (mistakenly giving your old phone number instead of your new one; attempting to change gears manually in a newly bought automatic)
What is the primacy and recency effect?
Primacy-Recency or the Serial Position Effect
When presented information in serial order, we remember more from the beginning and end of the list, at the expense of the intermediate items
What are the levels of processing?
Craik & Lockhart (1972) –
Depth of encoding determines later memory for information
Processing at encoding can be shallow or deep. The greater the processing the meaning of stimuli at encoding the deeper the level of processing and greater likelihood of later storage and retrieval.
Importantly Craik & Lockhart disagree that rehersal will improve LTM as it just repeats previous operation. BUT rehersal has beneficial effects but they are small and not for every type of memory e.g. Prospective Memory may not benefit.
What is long term memory?
There is a transfer process from working memory into long-term memory - as a result of rehearsal and elaboration
Very large capacity
Storage can be for a few minutes, but in theory can be for a lifetime
Why do we all have different memories of the same thing?
In general, meaning is encoded rather than exact representation
e.g. you’ll remember that you received a letter from your friend regarding a party this weekend, but you won’t remember the exact wording (Sachs, 1960’s)
Storage into long-term memory is known as consolidation
What is consolidation?
Involves structural change: the pattern of neural pathways are changed
Long term potentiation: strengthening of synapses, believed to be the cellular foundation for memory
Research in to how to induce LTP useful for dementia treatment
Rats given NMDA receptor antagonists display memory deficits. Mice bred with enhanced NMDA function show greater LTP and better memory
Requires metabolic activity for minutes/hours after the stimulus has been presented
Believed that the hippocampus plays a vital role in consolidation
How do you retrive?
Cue required (e.g. prompt, reminder, question)
Original stimulus reconstructed using information from cue
The more information available, the easier the retrieval
A good ‘filing system’ also aids retrieval
e.g. mnemonic’s (memory aids, Method of Loci)
Make something personally relevant to you and you’re more likely to remember it
Retrieval can be affected by interference
Proactive – new phone number replaces old number
Retroactive – old route home blocks new route home
Tip of the tongue phenomenon
Do not click on these until after session
What are the factors affecting retrieval?
Levels of Processing
The more something is elaborated at time of encoding, the easier it will be to retrieve
Organisation
Of concepts in memory (also, associations between concepts stored in LTM may facilitate recall)
Context
Being in the same place/emotional state as the time of encoding facilitates recall
State Dependent Memory
What are the declarative and non-declarative knowledge?
Declarative knowledge (sometimes known as explicit memory):
Memory for facts, for information that can be conveyed by statements
Involves conscious recollection of events / facts
Encompasses semantic and episodic memories
e.g. Your birthday
Non-declarative:
Generally doesn’t involve conscious recollection e.g. procedural memory
Implicit memory
Priming - Thinking of one thing makes you think of other things Eg. Doctor = nurses.
What is state/emotion dependent recall?
Information is better recalled when the individual is in the same state during encoding and retrieval – this includes both the environment and their internal mental state
E.G. works with drugs and alcohol too (Weissenborn 2000).
Godden & Baddely 1975 – Divers learned words on land and underwater – recall was best when the learning environment matched the retrieval environment.
What is procedural memory?
Procedural knowledge
Memory for how to do things/skills
Often in the absence of conscious recollection
e.g. How do you tie your shoelaces?
Driving
Riding a bike
Playing chess?
What are semantic and episodic memories?
Both forms of Declarative Memory
Semantic memory:
Memory for facts, ideas
what is the capital of Peru?
the meaning of the word ‘DOG’
Episodic memory:
Memory for events, situations – centered around you
your first day at university
what did you have for breakfast today?
What are episodic/autobiographical memory?
Most episodic memory decline over time however decline is not uniform over all memories e.g.
Bahrick et al (1975) – memories of student days showed remarkable preservation – Reminiscence bump = Surprising perseverance of memories occurring between ages of 10 and 30. Why?
What is the reminiscence bump?
Stability of early adulthood memories is remarkable
Why
Majority of first time experiences. Novelty is memorable because of the lack of proactive interference from previous learnings
More evidence for reminiscence bump for positive than negative memories (Bertsen & Ruben, 2002).
What is a flashbulb memories?
Flashbulb memory = detailed and extremely vivid memories regarding circumstances surrounding very shocking event e.g. September 11th.
Only occur with shocking and emotionally significant events. Evolutionarily adaptive?
Emotional arousal during encoding enhances retention
Also frequently rehearsed and talked about
One time events that you will remember you’ll happen. Eg. Where were you during 9/11?
What are recognition and recall?
Recognition:
Sensing that a stimulus has been previously encountered, sense of familiarity
Generally easier than recall, as information is contained in the cue
Recognition can be direct from a set stimuli or from a mental search of LTM store
Recall
Reconstruction of a stimulus using the information available from the cue and information from LTM
Checked by the process of recognition
Greater ‘cognitive demand’ than recognition
Recall can be direct from the cue or arise after problem-solving strategies have been employed
Memory is not entirely ‘stable’ and recall and recognition can be inaccurate
Eye Witness Reports (Loftus, 1979)
Participants watch a film of an accident, one includes a STOP sign, the other a YIELD sign. Using specific wording, you can change people’s memory:
‘How big was the stop sign by the road?’
The participant won’t remember the fact that they saw a yield sign
‘How fast were the cars going when they smashed in to each other?’
Participants will recall the cars were going faster than they actually were
How do you forget?
The main causes of forgetting from either working memory or long-term memory:
Passage of time
Rapid decay of information from WM
Cell death leads to loss of LTM (can be accelerated e.g. dementia)
Interference
Interference to storage in WM e.g. pro-/retroactive
Connections are remolded over time in LTM, influenced by pro- and retroactive interference of information
What happens to memory with ageing?
Pheonomena
Infantile amnasesia = inability to remember events from early childhood.
Generally people can not remember anything before 2 years. First memories usually occur between 2 and 5 years. Probably because brain regions responsible for episodic memory are not sufficiently developed.
Reminiscence bump = preserved memories for 10 to 30 years (many first time occurances)
Normative ageing
Speed of processing declines (Perfect, 1994)
Memory declines and forgetfulness increases but shouldn’t interfere with ongoing functioning
