Memory Flashcards
What is memory?
The ability to store and retrieve information over time
auditory memory
Echoic- hold info 3 sec
visual memory
iconic- holds info 250 ms
About neuronal architecture and memory…
- By learning something new your brain structure is being changed as new information is given and you form new axonal and neuronal connections which store the information.
- Neurones die over the course of life time, die all the time, memories not stored in one neurone for this reason otherwise they would be lost. Memory is instead stored in multiple neurones in a distributed process - neuronal network.
- You cant eradicate a memory by attacking a memory as you don’t know which ones its distributed within. Lose memories in illnesses such as dementia because so many have been lost, can lose up to 80% before you even notice the change. Whole sections can die and you would only notice that you’re slowing down. When someone presents with dementia they will have already lost over 50%, often whole sections.
- Neural architecture acts the same as the internet, there’s always multiple routes to the same neurone, so if one is blocked then it’ll take another one to get the information.
- Brain stores information at different levels of readiness. In Alzheimer’s and dementia lose the useless information first, and last the things you need all the time such as how to go to the toilet and the name of your partner. Your brain prioritises information based on utility and relevance to you.
What are the types of memory?
Iconic memory short term memory working memory immediate term memory long term memory episodic memory (autobiographical) semantic memory declarative memory procedural memory prospective memory
What is iconic memory?
this is the after image on retina if visual, tactile feeling on skin if you have been touched by something for long enough, echoic if you still hear a sound after it has stopped. These stores are very momentary, 250ms.
What is short term memory?
online storage for things that are happening now. Phone numbers originally 7 digits as can only remember 7-8 things for about 30 seconds (unless constantly sub-vocally rehearsed). 7 pieces of information +/- 2 (standard deviation) is the average limits of human memory. Short term memory is the old fashioned way of saying working memory
What is working memory?
three components: phonological loop (auditory info), visuo-spatial sketchpad (visual), and something resembling consciousness and attention. As there is a consciousness part this means conscious awareness is very limited, but unconscious awareness is vast (eg hearing name across the room even though working memory is full
What is immediate term memory?
a new form. This is the bit between working and long term. Stored for up to 2 days. Eg location of car in carpark
What is long term memory?
potentially forever eg Paris is the capital of France. Divided into separate sorts of stores (episodic/autobiographical which is events which have happened to you, totally separate to semantic memory which is factual memory eg paris - these two are functionally separate, can lose one and not the other
What is episodic (autobiographical) memory?
events which have happened to you
What is semantic memory?
factual memory
What is declarative memory?
things you know you know, when something is on the tip of your tongue
What is procedural memory?
memory for doing things such as riding a bike, driving, swimming
What is prospective memory?
ability to remember to do things in the future, e.g. important tasks you need to do late in the day/week
What is expectation in relation to memory?
Expectation is a memory phenomenon when you’re doing something and your brain fills in the information its expecting, eg hearing mum shout you or jumping when you see something outside at night. Also means that if you see someone out of context when you’re not expecting it you struggle to remember who they are or where you know them from.
There is evidence that human memory is rapidly declining due to technology, in particular google.
What are the critical concepts in neuropsychology in relation to memory?
- 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 by other related functions are preserved eg individual loses 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 and Plaut “the gold standard was always a double dissociation” 2009
What are the 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 form the memory system = stage 3
Forgetting can result from failure of any of these stages, rather than a process in itself.
About encoding and storing memories…
Encounter with initial stimulus you’re trying to remember eg a lecture, you’re trying to record it by paying attention in order to hopefully remember it.
The deeper the level you encode something to the level you remember it the better you remember it. To deepen the level of encoding you pay more attention, write notes, etc. asking questions makes you encode to a deeper level because you think about it I a deeper way as you have to search your memory for answers which activates similar structures which mean when you are told the answer you can hook it onto something. Making things personally relevant also means that you can encode things deeper.
Storage is transferred between types of memory. One of the best ways to store memory is by asking questions, doing practice questions, making it relevant to you and making notes (rehearsal not shown to have much effect). Consolidation is the transfer from short term to long term.
In retrieval the memory is reconstructed more than recollected, you are not accessing the exact same thing but just the jist of it. We reconstruct things, which we know by telling stories about things that happened - they change slightly. This tells us that human memory is not very reliable - scientific evidence from eye witness testimonies which are very inaccurate in at least 50% of cases.
What we think of as forgetting can result from failure at any of these stages.
About memory structure
A basic model is the multi-store model of memory (Atkinson and Shriffin, 1974)
sensory inputs > sensory store >(encoding)> short term memory (retrieval) long term memory
When gets to long term memory, long term memory has capacity which is almost infinite if you can always lay down memories.
Have done studies to try and test the capacity of this, by showing around 10,000 faces you’ve never seen before, and then the next week they show you them and ask if you’ve seen them before, and they keep increasing the number over months and they haven’t found the capacity of limitation.
What is sensory memory?
- Auditory [echoic] memory - holds information for approximately 3 seconds
- Visual [iconic] memory - holds information for approximately 250ms
Have all the other modalities too, but there is very little research on them because it is very rare. 50% of brain is vision so 90% research on vision, 10% on auditory, very little on olfaction. Smells are weirdly one of the most infallible sources of memory however.
About short term memory
• STM - now termed Working Memory (Baddeley and Hitch, 1974)
• This consists of three components:
- Central executive: this resembles what we would call ‘attention’
- Phonological loop: holding information in a speech-based form
- Visuo-spatial sketchpad: specialised for holding cisual and spatial information
Older form, more historical but still know it.
Central executive - this is almost a representation of consciousness/attention. Attention is a way of deepening the level of encoding. The brain pays most attention to information that is relevant to you. This biases us in terms of attention, means that what we see in the world is not what’s there but is what is interesting to us. If you change who you are as a person, you have trouble remembering things you learnt as your old self - this is called state dependent memory. Best example is locational memory - what you learn in this class, if you took the exam in the same room as the lesson then you would get about 5% more on the paper.
About 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)
- Be beware of chunking - grouping bits of information to make remembering easier
Chunking is how you group bits of information, for example not remembering each number in a phone number, but putting parts of the number together.
Inference in memory recall
Inference in WM
- Traces only remain in WM with repeated rehearsal (ie 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)
An example of interference is making the person think about something completely different when trying to remember something else - when new information interferes with old (retroactive) and when old information interferes with new information (proactive)
