We call "memory" that basic ability that most of us possess to recall knowledge as well as events that have happened to us in the past. Since we base our understanding on time as moving in one direction – forward – we rely on memory, the things we have learned in the past, in order to keep us moving in that forward direction. Everything that we do in the present relies on memories of what has happened or been learned in the past. The word "memory" is derived from the Greek myth of Mnemosyne. Mnemosyne was the mother of the muses. She was supposed to have complete knowledge of everything in the past, the present, and the future. Without memory, we would not be able to go through our day to day lives using abstract thinking and performing the most basic functions. Through our conceptual recollection of the past, we are able to communicate with other people and forge our own identities. What's more, memory is the starting point of all media in that it enables us to create something and understand what is being presented to us.
The way memory works is related to such parts of the brain as the frontal lobe, the temporal lobe, the cortex, and the hippocampus. We can classify memories in to three different types: sensory, short term, and long term.
When we speak of "sensory memory," we are referring to the few split seconds that follows the initial perception of an object. If you are able to briefly look at something and immediately memorize its details, then that is an instance of sensory memory. Typically, in these cases, when you are only able to see something for a few split seconds, you might feel like you saw a lot more than you are able to describe. Using a special experiment involving a "partial report paradigm," the researcher George Sperling conducted some vital experiences in the realm of sensory memory. Sperling arranged a dozen letters in to three rows of four. He then played either a low, medium, or high tone, which would be their cue for what row of letters they were supposedly to recite. The result of this experiment was that most humans can process at least twelve items with sensory memories, but that this begins to degrade at quite a rapid pace.
Some of the data that is perceived in a sensory memory will will be transferred to a short term memory. We call short term memory the ability to recall something from several seconds to a minute ago. Usually four or five objects can be stored in short term memory, although that number can be increased by a process that psychologists have come to call "chunking." If a group of letters, for example, is presented in meaningful rows instead of just scrambled, we can usually remember them for a lot longer.
Finally, there is long term memory. Unlike short term and sensory memories, which disappear in a brief amount of time, long term reflections to memories that can be stored for a period of up to several years.