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Memory is the ability of the brain to encode, store and retrieve information when required.

There are three types of memory:

1. Sensory memory - takes in all visual and auditory information received for a few seconds
2. Short-term memory - can hold about 7 items for about 30 seconds
3. Long-term memory - can hold an unlimited amount of information for a very long time

Your sensory memory takes in all visual and auditory information received for a few seconds and only a fraction of the sensory images formed are then committed to short-term memory. These are then either transferred from short-term memory (STM) to long-term memory (LTM) or discarded.

Memories can be lost by:

1. displacement - older information is pushed out by new information
2. decay - memory traces breakdown when groups of neurons are activated