Memory

Long-term memory has been the focus of most research and theory on the memory system. It holds all the information that has managed to pass through the sensory and short-term memory systems. In contrast to both of those systems, long-term memory is thought to be able to hold potentially unlimited amounts of information for an indefinite period of time, possibly for a lifetime. It is thought to hold all of the memories of our life, as well as our knowledge of the world in general. In long-term memory one might find memories as diverse as the first person you ever had a crush on, knowledge of how to ride a bike or cook scrambled eggs, the names of the five great lakes of North America, or a second language. Indeed, long-term memory is often compared to an encyclopedia in terms of the amount and range of information it holds.

Long-term memory then stores and operates on very diverse types of information, and there are many theories as to how the different types of information are represented and organized within it. Research shows that long-term memory operates according to a number of different systems, and researchers disagree as to exactly how it should be divided up. Yet there are some very influential theoretical divisions of long-term memory that are now widely accepted. These are the divisions between procedural memory, episodic memory, and semantic memory.