Procedural memories tell us how to perform a particular activity. Procedural memories usually do not include where and when the procedure was learned. Also, we usually cannot easily describe the contents of a procedural memory in words. For that reason, procedural memories are considered to be implicit memories. The memory usually includes what happened along with when and where it occurred.
Semantic memories are facts, figures, concepts and definitions.
Facts are usually stored without information about when and where they were learned. Explicit and implicit memories may involve different brain systems. Clustering Items recalled from long-term memory are clustered or grouped. The clustering is based on some logical association between the items. In this model, each concept is linked with a set of others, which are in turn linked to still others.