Characteristics of Sensory and Short-Term Memory

The theory first proposed by Richard C. Atkinson and Richard M. Shiffrin about varying levels of memory posits that there are three levels: sensory memory, short-term memory and long-term memory. The function and characteristics of each type of memory are explained in an analogy that rests on an individual mind's reaction to a given stimuli, an outside agent that has an effect on and is interpreted by the human mind.

Cognitive Processes

• Both the sensory and short-term memory levels are dependent on cognitive processes. Cognitive processes are defined by The Free Online Dictionary by Farlax as, "the performance of some composite cognitive activity; an operation that affects mental contents; the process of thinking; the cognitive operation of remembering." The cognitive process is what allows the mind to transport information about the stimuli from each level of memory, from sensory to short-term to long-term. The cognitive process selects some information to be retained and discards others to be forgotten.

Sensory Memory

• Sensory memory, the first level of memory, describes the short-lived impression a stimulus leaves after it is gone. For example, the smell of food remains in the sensory memory a short while after it has been consumed and people remember what an object looked like to them after they have walked past it. This information is sensory and the sensory memory is photographic or echoic -- with hearing -- lasting about 500 milliseconds. The defining characteristics of sensory memory are its brevity, the fact that it is uninterrupted information, that it is memory registration of data processed visually and that it is a high capacity form of memory registration. Sensory memory is like the mind taking a snapshot of stimuli and storing it for less than one second, unless it is converted and transferred to another level of memory that can be recalled for later usage. This is done by processing the stimuli, examining and paying attention to its features and later attempting to recall it.

Short-Term Memory

• Short-term memory, also called working memory, is where awareness lives. This can be the awareness of thoughts, feelings and sensations. The distinction of short-term memory is its limited storage, as compared to sensory, and its ability to only hold onto a limited amount of information at once. By the time the unprocessed information in the sensory memory is transferred to the short-term memory, it has been encoded by the cognitive process. Short-term memory retains information for about 20 to 30 seconds until it is dealt with further and passed on to the long-term memory. Short-term memory is comprised of both content, the data a person can immediately be aware of and process, and work space, the mental "work bench" where one interacts with the data.

Memory Troubleshooting

• Any problems in short-term memory might impact a person's ability to process and retain stimuli experienced by sensory memory. For details of information to be held in the more-expansive and longer-lasting, long-term memory level, they must first be processed through sensory and short-term memory.