Thank you for personally requesting me to answer this question. Here is the answer:
Memory is a three step process broken down into sub groups. It begins with perception which is influenced by your personality, genetics, and even your culture. The first part of the formal process is called encoding where your brain assigns meaning to the perception and assigns, like a computer, codes to prepare for storage. The second step of the process is storage where the brain, typically through the hippo campus, stores the encoded information for later access. The final step is called retrieval where the stored information is pulled back and accessed.
Within all three of these processes there are subprocesses, including for example, with encoding you can encode visually, auditory, or semantically. For example, someone asks you to remember Niagara Falls. You can first see a picture of the falls in your mind, then if you wish you can add sound to hear it, then also understand your friend's comment that your basement, after a flood, looks like Niagara falls.
Memory is compromised most often by inadequate retrieval cues often called tip of the tongue phenomenon. This is where material was not encoded strongly enough. Age, also deteriorate some memories because the webs of association with each memory deteriorate over time. For example, you may no longer remember your first grade teacher's name because you have not maintained the web associations links.
Lastly, we believe that rapid eye movement sleep helps transition memories from the hippo campus into long term storage. How this works exactly is unknown, but the presence of acetylcholine (ACH) may influence your brain's ability to store memory. This is why you should never take benadryl the night before a test. Benadryl blocks ACH and prevents memories from being stored adequately.
Sometimes old memories interfere with the development of new memories (proactive interference). For example, you learn a new name and can't remember the old name.
I hope this has helped you,
Edited by Kate McCoy, M.Ed, NBCC, LPC on 12/30/2010 at 1:00 PM EST