Why are people more outgoing when they are young than old? Robin Hanson attempts an answer:
As you reveal more to strangers, the distribution of their evaluations spreads out, some moving up toward friends, others down toward enemies. You want to reveal more to potential friends in the hope that some of them will rise above the friend threshold, but you do not want to reveal to potential enemies, for fear they will fall below the enemy threshold. Once people do cross these thresholds, however, your preferences about revelation switch. You want to stop revealing things to confirmed friends, for fear of losing them, and you want to reveal more to confirmed enemies, in the hope of winning them over.
So when looking for someone to marry, you’ll want to open yourself to people. And to help this process, you’ll want to learn about yourself. Once you are married with children, however, you will not want to learn or reveal more about yourself. Similarly, when searching for a new career or entry level job, you’ll want to reveal yourself, but once tied to a career or workplace, you will not want to learn or reveal more. When moving to a new neighborhood you’ll ponder what you really want, but once you live there you will not want reveal too much to neighbors, or think too carefully about how much you like them.
This may go a long way toward explaining standard life cycles in openness and conformity. The young discover and celebrate their passions and uniqueness, except not always with their old friends. The old prefer stability and conformity to community, and reveal and discover the most (in private) with their deepest adversaries. To the young the old will seem boring and conformist, while to the old the young will seem lonely and flighty. The young and the old can really be the same sort of people, but in different circumstances.