Consider the following questions: Do acorns have stems? Do you tune a guitar by tightening and loosening the strings? Do deer have white noses? If you were able to answer these questions correctly (yes, yes, no), then you were using semantic memory. Much of semantic memory relates to the brain systems that enable us to store and retrieve semantic knowledge. This article explores the neurobiology of this process.

Multiple Long-Term Memory Systems

When you remember that acorns have stems, you are using your semantic memory. When you remember the time you gathered acorns with your father in fifth grade, you are using your episodic memory. In both cases you are retrieving information from long-term memory. Are there, in fact, two separate memory systems for these two types of memories?

In 1972, the psychologist Endel Tulving first argued that there are two separate memory systems. Tulving...