(This page last updated 12 October, 2006.)
"Chunking" is a way to organize information into larger units. It increases the amount of information that can be active in Working Memory.
Holding a 10-digit string in Working Memory is difficult or impossible: 4 2 5 7 4 7 1 9 1 0
However, we can split, or "chunk", this string into subunits:
425: Kris' office number
747: a model of airliner
1910: the year that William James died.
If you already have those numbers stored in Long Term Memory, then holding the 10-digit string in Working Memory becomes much easier.
Note: As the size of the chunks go up, the number of chunks that can be stored go down slightly. There is a small price to be paid for using chunking.
The use of chunking to increase memory capacity shows that there
is flexibility in what type of information is stored in Working
Memory.
If there is a complex combination already encoded in Long Term Memory
(such as a word or number), it can be stored in Working Memory as a
single item.
It is easier to hold this string of words in Working Memory:
cat, truck, house, fly, clock, sound, bump
than this string:
screwdriver, Constantinople, ironing, dilapidation, ignition, Jerusalem, gentrify
Why is that?
Words that take longer to say are also harder to hold in Working Memory, suggesting that the info is stored in an auditory format. It is as if you speak the words quietly to yourself, and store them in a memory buffer.
Reisberg refers to the mechanism for loading the info into Working Memory as the "inner voice". Because this buffer stores the sounds associated with the words, we will call it the "Phonological Buffer". It can hold a string of sounds of a certain length. It is easier for the inner voice to store short words than long words.
For info to be retrieved from the Phonological Buffer, there has to be an "inner ear." When it is time to recall the stored info, the "inner ear" routes it to the Central Executive.
The Central Executive can perform a wide variety of cognitive functions.
Once it has received the info from the Phonological Buffer, it may decide to rehearse it by sending it back to the Phonological Buffer. The loop from Central Executive to Phonological Buffer and back allows for repeated rehearsal.
The presence of the Central Executive helps to explain how rehearsal works, but are also other reasons for having a Phonological Buffer that is separate from the Central Executive. It explains why we can store phonological information while still performing other tasks.
The Phonological Buffer is probably not the only Working Memory storage area. We are also able to store visual and spatial patterns.The storage for these types of memories has been called the "visuo/spatial scratchpad". The Central Executive can store and retrieve information using the Visuo/Spatial Scratchpad, just as it does with the Phonological Buffer.
next class: Getting Into Long
Term Memory
Psych 315: Cognitive
Psychology 
Kyle Cave
Psychology Dept.
U.
Mass.