Secondary memory

Secondary memory (or long-term memory) is often defined as the opposite of short-term memory. Short-term memory is measured in minutes, whereas secondary memory capacity is almost unlimited, like its length.
Secondary memory is often divided into several sub-categories depending on the type of information stored:

- Nondeclarative memory (or implicit memory) results in an unconscious and natural learning process. It includes procedural memory and memory of skills that seem to be absolutely natural once they are learned, such as cycling and reading.

- Declarative memory is also called explicit memory, because it implies an explicit process of recall. It includes facts, data, and experiences and often involves a conscious process of learning.

- Of the long-term memories, episodic secondary memory is the memory of personal events and episodes in our lives.