Memory is essentially the capacity for storing and retrieving information. Three processes are involved in memory: encoding, storage, and retrieval. All three of these processes determine whether something is remembered or forgotten.
Processing information into memory is called encoding. People automatically encode some types of information without being aware of it. For example, most people probably can recall where they ate lunch yesterday, even though they didn’t try to remember this information. However, other types of information become encoded only if people pay attention to it. College students will probably not remember all the material in their textbooks unless they pay close attention while they’re reading.
There are several different ways of encoding verbal information:
After information enters the brain, it has to be stored or maintained. To describe the process of storage, many psychologists use the three-stage model proposed by Richard Atkinson and Richard Shiffrin. According to this model, information is stored sequentially in three memory systems: sensory memory, short-term memory, and long-term memory.
Sensory memory stores incoming sensory information in detail but only for an instant. The capacity of sensory memory is very large, but the information in it is unprocessed. If a flashlight moves quickly in a circle inside a dark room, people will see a circle of light rather than the individual points through which the flashlight moved. This happens because sensory memory holds the successive images of the moving flashlight long enough for the brain to see a circle. Visual sensory memory is called iconic memory; auditory sensory memory is called echoic memory.
Some of the information in sensory memory transfers to short-term memory, which can hold information for approximately twenty seconds. Rehearsing can help keep information in short-term memory longer. When people repeat a new phone number over and over to themselves, they are rehearsing it and keeping it in short-term memory.