The main three systems of operation of memory are known as the Multi-Store Model (Atkinson & Schiffrin 1968), the Working Model of Memory (Baddeley & Hitch 1974), and Levels of Processing Model of Memory (Craig & Lockhart 1972). Multi Store Model Figure [ 1 ] http://www. smartpsych. co. uk/wp-content/uploads/2010/04/msmmodel2. png Key features of MSM: * Three types of memory stores – sensory, short term and long term (any stimulus must pass through one or more of these in sequence).
Each store retains a different amount of information based on how much the store can retain. * Each of the stores retains a different amount of information in a different way and for a varying length of time. The sensory memory is responsible for taking the information from one of the sensory organs and holding it in that format, prior to transferring the data to the short term memory, and then dependent on the form of rehearsal (either by maintenance or elaborative rehearsal), is stored in either the STM or LTM.
The information from any one of the sensory organs is encoded into the STM as one of the following: * Iconic (visual) stored as an image. * Echoic (acoustic) Auditory input from the ears and stored as a sound. * Taste * Haptic (touch) * Smell An example of Iconic sensory storage was demonstrated by Sperling (1960), whereby he tested participants by using a tachistoscope which flashed pictures onto a blank screen for a very brief amount of time.
He then tested them on their ability to recall as many of them as possible from a grid of twelve that he would display for one twentieth of a second. His findings showed that whilst they could only recall approximately four images, the overall suggestion was that they had seen a lot more, but not enough time to record them. The presentation of the images was followed by three tone levels of high, medium or low which instructed the participants which rows they should focus their iconic memory on. Recall rate recorded was on verage three out of the four symbols from any one row, which suggests that the iconic store has a retention capacity of approximately 76%.
Sperling reported that if a delay occurred between both the presentation of the grid and the sounding of the tone then an increasing amount of information would be lost gradually (50% after 0. 3 seconds and 67% after 1 second delay) (Baddley, 2002). The short term memory has a retention duration of 0-18 seconds, and a capacity of 7(+/-2), as demonstrated by Miller’s (1956) experiment of chunking.
He discovered that our capacity to retain information can be increased by chunking large amounts of information together, otherwise referred to as trigrams (3 letter combinations). The length of time information can be retained is only a few seconds in the STM if not rehearsed, whereas rehearsal can increase that from anywhere from a few seconds too years. Peterson and Peterson (1959) found that the STM fades in under half a minute if not rehearsed, within 3 seconds this is reduced by 80% and only 10% of information remains after 18 seconds.
The LTM (long term memory) has an unlimited duration and capacity, although these memories can decay over time and become displaced (shunted out of the way in place of new ones). Long term encoding can be semantically associated in which by we link things together, such as school, tie, and teacher. Although there is the possibility of incorrectly making additional connections dependent on the individual LTM and what is personally associated with the key word.