Types of Memory
The three major types of memory are: sensory memory, short-term memory, and long-term memory.
Sensory Memory
Sensory memory is the first level of memory. The information is stored temporarily. Although there is a large capacity for sensory memory, it is temporary because most of the information is unprocessed.
Example: If someone is reading to you, you must be able to remember the words at the beginning of a sentence in order to understand the sentence as a whole. These words are held in a relatively unprocessed sensory memory.
Sensory memory can be divided into two subcategories: iconic memory (visual sensory memory) and echoic memory (auditory sensory memory). Iconic memory usually lasts less than one second while echoic memory lasts about four seconds.
The next step to remembering information longer and more effectively is to transfer sensory memory into short-term memory.
Short-term Memory
Short-term memory contains information that is actively being used at the moment. It can also be called working memory. The capacity for short-term memory is quite small, only seven, plus or minus two, items at a time. These items can be numbers, letters, words, etc. Information usually stays in short-term memory for about twenty seconds without a lot of rehearsal. An effective way to increase short-term memory is to use the method of chunking which is described under Improvement Techniques.
If information is to be stored for later use, information in short-term memory needs to be transferred into long-term memory.
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Long-term Memory
Long-term memory is the permanent storage place of all the information that has already been processed in sensory and working memory. The capacity of long-term memory is relatively limitless. Information becomes stored into long-term memory by rehearsal and association. These memories can last up to a lifetime. Long-term memory is divided into two subcategories: declarative, also known as explicit, and procedural, also known as implicit.
Declarative (Explicit) Memory
The recalling of factual information such as dates, words, faces, events, and concepts is known as declarative memory. It is memory that is consciously available. Declarative memory has two subdivisions: episodic and semantic. Episodic memory is the recalling of personal facts such as a birthday party. Semantic memory is the recalling of general facts such as the rules for playing volleyball.
Procedural (Implicit) Memory
Procedural memory is memory of how to do things such as swimming or riding a bike; it does not require conscious effort to remember.
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