Professor Eric Kandel discusses the importance of attention in forming declarative/explicit memories. These memories involve the hippocampus.
Attention is important for several aspects of learning and memory storage. When you learn something you encode the information and that itself requires attention. But in addition, recall of memory also requires attention. So, attention is absolutely critical. It is particularly critical for a form of memory we call declarative or explicit memory storage, which is a memory about people, places, and objects - it is a memory that involves, critically, the hippocampus.