Memory

  • Information Processing Model: Sensory, Working, and Long-term Memory
  • Information processing model proposes our brains are similar to computers. We get input from environment, process it, and output decisions.
    • First stage is getting the input – occurs in sensory memory (sensory register). Temporary register of all senses you’re taking in.
    • You have iconic (what you see, lasts half a second) and echoic (what you hear, lasts 3-4 seconds) memory
  • Working memory is what you’re thinking about at the moment.
    • Verbal info – any words + numbers in both iconic and echoic memory
      • Is processed in the phonological loop.
    • Visual + verbal info – Need coordination of the two – the central executive fills that role.
      • Creates an integrated representation that stores it in the episodic buffer to be stored in long-term memory.
    • Visual + spatial info are processed in the visuo-spatial sketchpad
  • Magic number 7 – can hold 7 +/- 2 pieces of info at a time. Why phone #s are 7 digits long.
  • Explains the serial position effect (primacy and recency effects)
  • The dual coding hypothesis says it’s easier to remember words associated with images than either one alone.
    • Can use the method of loci – imagine moving through a familiar place and in each place leaving a visual representation of topic to be remembered.
  • Final stage is long-term memory. Capacity is unlimited. 2 main categories: explicit (declarative) and implicit (non-declarative).
    • Explicit Memory (Declarative) – are facts/events you can clearly describe.
      • Anytime you take vocabulary test or state capitals you’re using semantic memory (has to do with words). So remembering simple facts.
      • Second type is episodic memory (event-related memories).
    • Implicit memories (Non-declarative) involve things you may not articulate – such as riding a bicycle, procedural memories.
    • Other is priming – previous experiences influence current interpretation of an event.
  • Encoding Strategies
  • Encoding is transferring sensory information into memory.
    • If you want to remember more than 7 things, need to process that info so it stays in long-term memory.
    • Rote rehearsal –You say same thing over again.
      • Least effecive
    • Chunking – we group info we’re getting into meaningful categories we already know.
    • Mnemonic Devices – imagery (crazier the better), pegword system (verbal anchors like words that rhyme with the number – 1 is gun), method of loci (tying info to locations), acronym
    • Self-referencing – think about new info and how it relates to you personally.
      • Also preparing to teach – learning it as if to teach it to someone else (putting more effort into understanding + organizing info)
    • Spacing – spreading out studying to shorter periods.

 

  • Retrieval Cues
    • Priming – prior activation of nodes/associations, often without our awareness.
      • hearing apple and asked to name word starting with A
    • Context – the environment you encode and take the test.
      • Scuba divers who learned and tested on same place scored better than learned in one place and took test in another.
      • But not always the case, if you can’t take test in same place studying in different places gives you diff cues for retrieval – so multiple cues that will help you.
    • State-dependent Memory – your state at the moment.
      • If you learn something while drunk you’ll remember next time you’re drunk. Or combining a mood with an advertisement – next time you’re in that mood will remember the product.
  • Retrieval Cues: Free Recall, Cued Recall, and Recognition
  • Anytime you pull something out of long-term memory, you’re engaging in retrieval.
    • Free recall – no cues in recalling.
      • Better recalling first items on a list (primacy) as well as last few (recency). Harder in middle.
      • Curve is called the serial position curve/effect
    • Cued recall – give you “pl” for “planet”.
      • Get more retrieval cues, tend to do better than free recall.
    • Recognition – best out of the 3 tests.
      • Present two words, and say which one you heard.
  • Memory Reconstruction, Source Monitoring, and Emotional Memories
  • Brain doesn’t save memories exactly. Every time we retrieve a memory we change it in small ways, according to our goals/mood/environment. Or due to our own desires. If gap brain fills it in with something desirable.
    • Sometimes information we retrieve is based on a schema – mental blueprint containing common aspects of world, instead of reality.
    • False information – inaccurate recollections of an event.
    • Misleading information – observed video of car crash, and asked how fast cars were going. Some people got word “hit” and some got “smash”. If people received “smashed”, more likely to say there was glass on the ground.
    • Source monitoring Error – memory error where source of memory is incorrectly attributed to a specific recollected experience (when people recall information they often forget the information’s source) –
      • angry with someone but forgot it happened in a dream. Or recognize someone but don’t know from where.
    • Emotional memories can be positive or negative
      • Highly vivid memories are called flashbulb memories – even if they seem as real as life, still susceptible to reconstruction.
  • Long Term Potentiation and Synaptic Plasticity
    • Brain doesn’t grow new cells to store memories – connections between neurons strengthen. Called long-term potentiation, one example of synaptic plasticity.
      • Neurons communicate using electrochemical signals – through synapse. Pre-synaptic neurons release neurotransmitters on post-synaptic neurons, allowing Na and Ca to flow in. Dif in charge between outside and inside is the
    • With repeated stimulation, the same pre-synaptic neuron converts into greater post-synaptic neuron – stronger synapse, and when it lasts longer called long-term potentiation. This is learning!
  • Decay and Interference

Decay – when we don’t encode something well or don’t retrieve it for a while, we can’t at all anymore. Connections become weaker over time. Initial rate of forgetting is high but levels off over time.

  • Ebbinghaus was first investigator of decay. Found his rate of forgetting very fast, but if he remembered it after initial stage it levelled out.
  • Just because you can’t retrieve something doesn’t mean it’s completely gone – relearning. Even if Ebbinghaus couldn’t reproduce everything, took less time to learn list second time around. Called savings.
  • Works with procedural skills too – ex. With piano.

Sometimes interference is the problem though – 2 types:

  • Retroactive – new learning impairs old info (ex. Writing new address)
  • Proactive – something you learned in past impairs learning in future (Ex. New password).
  • Aging and Cognitive Abilities
    • Stable – implicit memory (ex. riding a bike), and recognition.
    • Improve – semantic memories improve around age 60, so older adults have better verbal skills. Also crystallized IQ (ability to use knowledge and experience). Also emotional reasoning.
    • Decline – recall, episodic memories (forming new memories is difficult, old memories stable), processing speed, and divided attention. Also prospective memory (remembering to do things in future) is decreased.
  • Alzheimer’s Disease and Korsakoff’s Syndrome
  • Excessive forgetting can be problematic.
  • Dementia is forgetting to point of interfering with normal life – results from excessive damage to brain tissue, ex. From strokes.
    • Most common form is Alzheimer’s Disease. Neurons die off over time. Earliest symptoms are memory loss, attention, planning, semantic memory, and abstract thinking. As it progresses, more severe language difficulties and greater memory loss, emotional stability and loss of bodily functions. Cause is unknown – have buildup of amyloid plaques in brain.
  • Korsakoff’s Syndrome – caused by lack of vitamin B1 or thiamine. Caused by malnutrition, eating disorders, and especially alcoholism.
    • Thiamine converts carbohydrates into glucose cells need for energy. Imp for neurons.
    • Damage to certain areas causes poor balance, abnormal eye movements, confusion, and memory loss. At this stage called Wernicke’s encephalopathy – precursor to KS. If diagnosed in time can prevent further damage. If untreated, will progress to Korsakoff’s. Main symptom is severe memory loss, accompanied by confabulation (patients make up stories to fill in memories).
    • Treatment is healthy diet, abstain from alcohol, take vitamins, and relearn things.
  • Retrograde amnesia is inability to recall info previously encoded, anterograde amnesia is inability to encode new memories.
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