Historically, how have people thought about ‘working memory’?
Contrast primary memory with secondary memory (James, 1890).
William James distinguished between primary and secondary memory and how each
linked up with consciousness. Primary memory is directly accessible to consciousness (it
is in your mind, you can think about it). Secondary memory is more like long term
memory, a form of crystallized memory. This memory is not conscious to you unless you
bring it up into primary memory temporarily.
In the 1960’s people started talking about long term and short term memory instead of
primary and secondary memory.
The Magical Number Seven, Plus or Minus Two (Miller, 1956). This experiment occurred quite a
bit before the birthday of cognitive psychology in 1969.
An investigation of the capacity of STM (now termed working memory)
Reported capacity to be approx. 7 items (people seem to have a working memory
capacity around 7. Some people are a bit better, some are a bit worse. It didn’t seem to
matter what the content was in this experiment, the span would remain the same)
But what counts as an item? (an individual letter? Or 7 words with many letters?)
Chunking can cram more info ‘into’ an ‘item’ (letters can be bound together in a word to
become an individual entity. Therefore we can remember 7 units of information)
Historically speaking, what was the proposed relationship between STM and LTM?
The following is a diagram that captures main aspects of the memory system as thought of in the 1960’s.
Specifically, this is the Atkinson and Shiffrin model (1968) aka the modal model. Input goes into the
system and into sensory memory. The arrows represent a transfer of information. Sensory memory was
meant to be a very short form of memory, and there was a different store for each different sensory
modality (although the focus was mostly visual at this time). Information is not stored for more than a
few hundred milliseconds in this store. Sensory memory is what allows you to see an entire circle when
a firecracker is spun quickly in a circle. There is rapid decay in this store.
Information goes from here into short term memory. This area holds information for a longer period of
time (from 3-6 seconds without rehearsal). If the individual engages in rehearsal, information can stay in
this store indefinitely.
Information can go from here into long term memory, but it is not transferred, but “faxed”, because
there are copies in both short term memory and long term memory. This is why the arrow is double
ended. When we need information it can be pulled from LTM to STM to work with. In this model, short
term memory does not include the active process that our conception of working memory includes.