MEMORY - L4

MEMORY - L4

1. broad complex, involved whenever past experience influences later behaviour or mental processes

2. THE FIRST STUDIES OF HUMAN MEMORY

   • HERMANN EBBINGHAUS (1885) - interested in the relationship between time and forgetting under different experimental conditions, learned made up syllables/words e.g. BIM, KAJ Levels out – the forgetting curve slowly goes down – it doesn’t just drop straight down – LTM fairly stable. plotted 'learning' and 'forgetting' curves

3. POST COG REVOLUTION

   • MEMORY = information flowing through a system, information processing view, input --> process --> output, encode, store, retrieve
     • ATKINSON & SHIFFRIN (1968) - multi-store model - modelled the basic architecture of the memory system - each differs in duration, capacity and Sensory stores --> decay --> --> Short lived memory register that supports initial processing of environmental stimulation
       • Visual sensory memory – iconic store • Increases the time visual information is available to us • Revealed by “visual persistence” o Apparent continued presence of a stimulus beyond its physical duration • Parallel in audition = echoic store Sensory store is holding info a bit longer to register and see it. No sense of interruption – don’t instantly have a break as soon as it disappears.
         • SPERLING (1960) - what is the capacity and duration of sensory memory?
           • letters flash up 4x4, if caffeinated and ready to go would remember about 4 items. the rest would just fade away. observes could report 37% of the items. equivalent to remembering about 4 items in an array
           • partial report condition - only need to remember 1 of the rows with a noise --> observers could report 82% of the letters in a cued row, equivalent to remembering about 10 items in an array.
             • Evidence that people have access to the visual info after its gone. Gives us a paradigm for investigating the limits of this ability -- Future studies report that this advantage may last up to 1600ms post stimulus (e.g. Landman et al., 2003) ------ more common estimates <1000.s
               • when they have a que to a stimulus, you would remember about 10 items – access to visual information after it was gone

4. SENSORY MEMORY - very short lived, brief sense of it

   • high capacity but very short lived (rapid decay), first step in perception, collects information to be processed, holds information for initial processing, attention transfers small amount to STM
     • short term-store - long term store
       • confident that it was two systems --> neuropsychology - clear distinctions from short and long term stores function Other evidence for multiple memory sores – experiments with typical populations e.g. dissociations in free recall . • Memory is better for words presented at the beginning of the list (primacy effect) and at the end (recency effect)
         • THE RECENCY EFFECT
           • • Words still in STM --- Confirm this by testing after a dela,y, 30 seconds --- STM is only brief, so effect should be disrupted (prevented rehearsal by counting backwards after list) --- Recency effect disappears – reflection of being held in short term memory
         • THE PRIMACY EFFECT
           • • Words are already transferred to LTM ---- Test this by reading word lists more slowly --- More time for rehearsal should boost the primacy effect --- Process of rehearsal allows the words to be transferred to LTM --- Words at the beginning are being transferred to LTM

5. PROPERTIES OF STM

   • CAPACITY
     • MILLER. 1956
       • • Digit span experiments. Capacity = 7+/- 2 items “magic number.” --- Unit of capacity of STM = the chunk. Functional capacity of STM is limited but can be boosted with efficient encoding of info. Becomes a sentence so it is only one unit to remember – think of chunking of information – make it a meaningful unit of information to slot in memory store
     • COWAN, 2001
       • there is a limit to the capacity of stm, not limitless but hard to estimate, can boost storage with efficient encoding of info, -- chunking of info is key
   • DURATION
     • ‘Trigram’ Recall Task (Peterson & Peterson, 1959) • Goal = • Encode 3 letters (“trigrams”) • Count backwards by 3s from a number (‘Brown Peterson technique’ to prevent rehearsal) • Recall after different intervals • Prevent rehearsal – count back in threes - Stm is really good immediately but drops away by 18 seconds - Duration estimates tend to range from 15-30 seconds
     • LOSS
       • • Info sitting there, then gets displaced, becomes confusing then loss info • Performance is relatively good early on and gets gets worse over time o Some of this is due to decay • Some may also reflect proactive interference o Information displacement/loss due to competition from other items