WEEK 4 - Sensory Memory

• Memory


  Retention of experience-dependent internal representations over time
• William James distinguished between primary and secondary memory


  19th century
• Primary memory


  Things we are currently aware of, the current contents of consciousness e.g. what you can currently see in front of you
• Secondary memory


  Mental representations of the distant past that is not currently in our consciousness and must be brought back by a retrieval process e.g. name of your grade 3 teacher
• Types of memory


  • Short term/ working/ sensory memory
  • Long-term memory
• Types of long-term memory

  • Declarative explicit memory
  • Non-declarative implicit memory
• What is the multi-store model of memory?

  
• What does the Atkinson & Shiffrin Model tell us?

  -              There are multiple stores of memory

  -              We process information from outside world
• Sensory memory - all information/ stimuli goes into sensory memory

   

  Short-term memory - person focuses on some aspects of some information, discarding the rest

   

  information stays in short term memory as rehearsal is carried out through control processes e.g. repetition

  
• information is kept in long term memory via memorisation and remembered through retrieval from LTM to STM

  
• What is sensory memory? A buffer that briefly holds all information arriving at our senses

   
• What is the capacity of sensory memory? Very large, holds a lot of sensory information coming from our eyes and ears
• What is the timescale of sensory memory? 1-10 seconds
• What are 2 types of sensory memory stores?

  1.        Vision  iconic memory

  2.        Audition (hearing)  echoic memory
• What is the timescale for iconic memory? 1 second

  What is the timescale for echoic memory? 10 seconds 
• What is iconic memory? Sensory memory for visual information
• What is persistence of vision? We see the world as blended together, rather than flashes of images
• How does iconic memory explain persistence of vision? Iconic memory capacity of 1 second enables us to see the world as blended together as visual information is still active in working memory for 1 second as we see new things
• How is the duration of sensory memory tested? Through whole report and partial report
• What is whole report? When participants are asked to report as many letters as they can from the whole array
• What was the average score for whole report? 4.5 out of 12 letters (37.5%)
• What is partial report? When participants immediately heard a tone, which told them which row of letters to report
• What was the average score for partial report? 3.3 out of 4 letters (82.5%)
• What is delayed partial report? Tone was presented at a variable delay after the letters disappeared
• What was the performance pattern for delayed partial report? Performance rapidly worsens
• At delay tone of 0 (no delay in tone after presentation of letters), 82.5%

  At a delay tone of 100ms, significantly worse ~60%

  At a delay tone of 1 second, 37.5%

  
• What does partial report paradigm tell us about sensory memory to STM? People are able to selectively process some sensory information over others (depending on tone people hear, different information would go from sensory to STM)
• What is core to the modal model of memory? Output only comes from short-term memory, not sensory or long-term memory

   
• What is STM? Retains limited amount of information for a limited duration
• What is the capacity of STM? Limited

  What is timescale of STM? 15-20 seconds, short timescale
• What is a distinct difference between sensory and STM? Material held in STM can be rehearsed to extend the amount of time it is held for
• Is rehearsal conscious and effortful process? Yes 
• How is the duration of STM measured?

  -              Read 4 letters and try remembering them then a number

  -              After seeing the number begin counting backwards

  -              After a set time, you will be asked to recall the letters
• What are typical results of this experiment?

  -              When duration in which you count backwards is not long, 4 letters are typically remembered well (4/4)

  -              When duration in which you count backwards is longer, 4 letters are harder to remember (2/4)
• delay = how long people are asked to hold onto memory in STM

  
• How do we measure the capacity of STM? Digit-span task
• What is the digit-span task?

  -              Ask someone to hear you say numbers and repeat them

  e.g. you say 4,3 and then they say 4,3
• go through the series and see how many people are able to recall

  
• What is the typical result of the digit span task in measuring STM? People normally able to recall 5-9 items
• What is Miller’s law? People can remember 7 items +/- 2 items