Memory

Memory

1. Models of memory

   • The multi store model
     • Proposed by Atkinson and sheriff in 1968.
       • Memory is a flow of information through a system divided into into a series of interacting memory stores.
     • Each store has a different purpose and each varies in regards to coding, capacity and duration.
     • Sensory registers
       • Iconic Register - The memory of visual information.
         • Sperling
           • APRC
             • Aim - Investigate recollection of letters in a grid.
             • Procedure - Very briefly displayed visual arrays displaying three rows of letters. Asking the participants to recall what they saw after a certain period of time.
             • Results - Participants could recall 4 or 5 letters given 50 miliseconds but reported seeing more letters that they could not recall.
             • Conclusion - Visual memory is only available for a very short period of time.
           • GRAVE
         • Duration = 0.5 seconds.
       • Echoic
         • Sensory register for auditory information.
         • Darwin et al. - duration is 3 seconds.
     • Short term Memory
       • Information that is selected by sensory memory is transferred to the short term memory.
       • Temporary storage area which can be though of as immediate memory.
       • Holds everything that one is thinking about at any given time.
       • Encoding
         • Information is encoded acoustically.
       • Capacity
         • Short capacity first discovered by Jacobs in (1887)
         • Miller - Capacity is 7 +/- 2 chunks.
       • Duration
         • Atkinson and Sheriff - Duration is short, holding information for only a small amount of time while it is transferred to the LTM.
         • Hold information in STM through rehersal.
         • Rehearsal time does not mean retention in long term memory but the way in which you rehearse.
         • Peterson and Peterson
           • APRC
             • Aim - Investigate how long information is retained for in the STM without rehersal.
             • Conclusion - Information decays rapidly without rehearsal.
             • Results - Participants were able to recall 80% of the trigrams after a three second interval. After 18 seconds participants could only recall 10%.
             • Procedure - Presented participants with consonant trigrams, whilst they were counting backwards from a specified number. Participants asked to stop counting and repeat the trigram.
     • Long Term Memory
       • Anything that last longer than the duration of the short term memory.
       • Duration
         • It is very difficult to test the duration of long term memory.
         • Potentially never ending.
         • Bahrick et al. (1975)
           • 75 year old tested on their school classmates
           • APRC
             • Aim - Investigate the length of time that memories can be retained for.
             • Procedure - Tested 392 graduates of an American High school for their former classmates. Tested their memory of other students in their year book. Used various memory tests including recognition of class mates photographs.
             • Results - Participants performed remarkably well up to 34 years after with 90% accuracy. 48 years = 80% accuracy.
             • Conclusion - Shows that long term memory can be sustained for a long period of time. The drop could just be due to the aging of the individual rather than duration of LTM.
       • Capacity
         • No upper limit to the capacity of the LTM.
         • Memory is lost through decay but not the capacity of LTM reaching its limit.
       • Encoding
         • Semantic encoding is preferred in the LTM. Encoding based on the meaning of the information.
         • Baddeley (1966)
           • APRC
             • Aim - To investigate the possibility that LTM and STM encode in different ways.
             • Procedure - Badeley created a pool of words that were semantically similar, semantically dissimilar, acoustically similar or acoustically dissimilar. Asked participants to write down the words after hearing them. Each category had 10 words. HE waited 20 mins then tested to see what the participants remembered.
             • Results - The words that were similar were a lot harder to remember than words that were dissimilar. Acoustically had no difference however there was a definite difference between similar semantic recollection and dissimilar.
             • Conclusion - This means that memory in the LTM is coded semantically as the words that were similar in meaning interfered with each other.
     • Strengths and weaknesses
       • Strengths
         • A lot of studies around this model.
         • Brain damage case studies provide a lot of evidence for this model.
           • KF
         • Brain scanning techniques such as PET and MRI.
       • Weaknesses