Many of us have phone numbers in our heads that we will never forget. A number like 212-PE6-5000 will never be forgotten, as this was the oldest continually used business number in New York City. In my case, other numbers often come to mind, such as the phone number of the church I attended as a child. Recently, a number from the past started coming up, and I couldn't be sure of why I knew the number. So I did a reverse lookup on the number, and I found that it was the phone number used by the company my wife used to work for - over a quarter of a century ago. Even though the firm has moved out of its original area code region, they have kept this number so that long standing customers could easily reach them in their "new" digs.
This got me to thinking: What causes us to retrieve fragments of memories from "archival storage" and bring them into "working storage", and yet not be usable for much? In my case, I think it was an unplanned visit to a restaurant with my late wife's name that triggered recall of her former corporation's phone number. This number was the one I'd call during lunch hours, as it was the only one that would be answered by a human in this period. So, combined with a "successful" first date with a new lady, my subconscious mind may have been trying to signal its comfort with the new lady. Only a good shrink can say for sure....
There are so many things we file away in our memories, never (or very rarely) to be used again. For example, the phone number of the church I once attended brings back memories of their property before a medical office building was constructed on their former parking lot. My wife's corporate number brings back memories of her and that of the buildings that made up the factory where she worked. (She was part of office administration, but had to deal with all the headaches of NOT being part of the family that ran the business.) Yet, not all phone numbers are easily retrievable for me. For example, I can't remember any of the office numbers I used at work. Yet, I can easily recall the number of my tax preparer, a number which I would only use once or twice each year.
So what makes some memories retrievable and what prevents them from being retrievable. In my case, I think it is the importance the people connected to that number mean to me. I can not remember the land line number of my late wife's old apartment, as she moved into my place shortly after we met. Yet, I can remember her office number, as I was calling that number once or twice each day while she was at work. In the case of the church's phone number, I could use it to reach my mom while she worked at the church.
Sadly, I think that 212-PE6-5000 will never be as useful as it was in its heyday. As for the other numbers, all they do is bring back old memories.