Memory has been separated into three categories on the basis of the "amount of time the memory lasts." (Zhang, 2004, p.1) The three categories are stated to include the following: (1) sensory memory; (2) short-term memory; and (3) long-term memory. (Zhang, 2004, p.1) The focus of this brief study is to describe each of these memory storage processes. Sensory Memory & Short-Term Memory

Sensory memory is reported to act as "a buffer for stimuli received from the senses. A sensory memory exists for each sensory channel." (Zhang, 2004, p.1) Sensory memory is the shortest-lived of all types of memory and lasts only milliseconds to a few seconds. (Zhang, 2004, paraphrased) Iconic store is where visual images within sensory memory are stored for only a very short period and serves to integrate our visual experience. It is reported that in a presentation of three rows of four letters to subjects for 50 milliseconds that Sperling (1960) found that they were able to report four or five letters, but were aware that there were many more. (Zhang, 2004,, paraphrased)

Sperling discovered that this type of visual memory only lasted about one-half a second. Echoic store is where auditory senses are retained in sensory member for a short time. The estimation stated for the duration of echoic memory is approximately 250 milliseconds to one-half a second. Finally, the haptic store in sensory memory...

Zhang (2004) states that incoming memory is first held in sensory memory and through attention the information is then passed to working memory where it is processed.
II. Short-Term (Working) Memory

Short-Term Memory involves selective attention determining what information moves from sensory memory to short-term memory, which is often stored as "sounds, especially in recalling words, but may be stored as images." (Clark, nd, p.1) Short-term memory is reported to work basically the same way as the computer RAM (Random Access Memory) because it "provides a working space for short computations and then transfers it to other parts of the memory system or discards it. It is thought to be about seven bits in length.." Or otherwise stated, the individual generally remembers seven items. STM is reported to be "vulnerable to interruption or interference." (Clark, nd, p.1) Short-term memory can retains items indefinitely through use of rehearsal or repeating the information repeatedly. Working memory and short-term memory are held by some to be one in the same however, those who conduct memory research are reported to "often consider this a specialized term referring for information about the current task.

III. Long-Term Memory

Long-term memory is any memory that has been…