I turn 56 in a week, and I’ve been thinking about how life changes with age. I’ve come up with a view expressed in terms of two key distinctions:

Foregame vs. Endgame Actions in games often have both direct local immediate consequences, and also more indirect global delayed consequences, such as those that result from how other players react to your actions, then more others react to those actions, and so on. The longer a game that stretches ahead, and the more other players who interact, the more that these indirect consequences can matter. In contrast, at the end of a game there are fewer moves others make after you, and fewer other players that your moves might influence. So endgame play focuses more on direct local immediate consequences. Cooperation often breaks down in endgames, as it often depends on threats of future and wider reprisals against uncooperative behaviors.

Turbulent vs. Laminar When fluids like water flow slowly, their flow patterns tend to be simple, stable, predictable, and efficient. As one increases the pressure pushing a fluid while holding constant its environment, the flow velocity also increases, and at some point the fluid switches to flowing in complex, unstable, and unpredictable ways. Turbulent flows are less efficient; if you must pay to push fluids then you want to keep your flow laminar. But turbulent flows also mix fluids much better. Each part of a turbulent flow could end up in far more possible future locations, and next to far more other parts, than can similar parts of a laminar flow.

My view is: Young life is a turbulent foregame, while old life is a laminar endgame. That is, when young we are in the foregame of life, where our life paths are more turbulent, and when older we transition into the endgame of life, where our life paths are more laminar.

In youth, the main consequences of our actions tend to be indirect, global, and delayed. Especially important are social consequences such as what others think of us, and who allies with us. We can end up with very different reputations, mates, communities, occupations, industries, and so on. The life paths of young people also tend to be complex, unstable, unpredictable, and inefficient. For any one young person, it is hard to guess their future mates, jobs, communities, and status, and they may inefficiently change directions and paths many times.

In old age, in contrast, we tend to make fewer and smaller changes to our mates, jobs, communities, and status. We don’t adapt as much to changing opportunities as when young, but this is mostly reasonable given our many investments. We are mostly stuck with existing associates and allies, and wider communities involve themselves with us less. So while we need to worry about how our immediate associates will react soon to things we do, we don’t need to concern ourselves as much with wider more delayed circles. And even our immediate associates can do less to help or hurt us. So we focus more on direct, local, immediate consequences of our actions.

When young, we collect and explore many options, including in associates. We meet many people, and while we don’t want to commit to strong relationships with most of them, we like the option of exploring those possibilities more later, especially if these people should become powerful and high status. The mean value of a future association may be much larger than its median value. That is, we can sometimes mostly care about the chance that they will later become especially powerful or high status.

The young should be especially wary of creating enemies with powerful allies. So when young we tend more to endorse and adopt the standard social norms of our world, including those that say everyone that meets certain criteria should be treated with minimal respect, as if they might become high status someday. As a result, younger people acquire thicker longer distance networks of associations, which can create powerful incentives to seem and act cooperative on larger social scales. The future weighs heavily, and a wide social circle matters more. Also, since when young we understand the social world less, and a wider social world is more complex, we are then more worried about unexpected consequences.

When older, in contrast, we are less worried about wider social punishment of our behaviors. Fewer people matter to us, their and our life paths are more predictable, and we understand our smaller social world much better. So we can more directly calculate the consequences of what we do to people. Thus we are more willing to betray distant allies of allies, as we less fear their future reprisal. So when older we are more in a laminar endgame, where our actions are less guided by generic social norms on how to uniformly treat a wide circle, and more guided by calculating the personal consequences of doing particular things to particular people. For example, we need less to pretend that everyone might become high status, as it becomes safer to treat associates differently by their now stable status.

In many job promotion ladders, and also many other kinds of status ladders, previous status sets a rough lower bound on current status. Thus people tend to rise in status over time until a point in time when they stop rising and then mostly stay near the same status. In such cases, those who are still rising have a more turbulent life path, while those who have stopped have a more laminar path. This creates a correlation between status and turbulence. Thus high status people tend to have more turbulent lives, more like the lives of the young, helping to make the turbulent lives of the young seem higher status. And high status people can less see the age pattern I’m describing.

If you are young, you might wonder how much people do things because they are good people who really believe in the morality of the standard norms, as opposed to doing things out of fear of social reprisal. You might wonder in particular what your associates would do to you if they less feared such reprisal. Good news: when older you will have much clearer data on this. And typical older people around you also have data now, if you will ask them. Haven’t asked? Perhaps you don’t like the answer you think they will tell. Or maybe you don’t trust them to tell you the truth. (And if they’d lie, which theory does that support?)

In the above, I have told a functional story about how behavior should reasonably change with age. However, I should admit that human behavior has not adapted very much to big changes that appeared only in the last few centuries. One of those big changes is that young lives are far more turbulent than those of our forager or farmer ancestors. So turbulent in fact as to call into question the plausibility of social reprisal. For example, high school students often invest greatly in their social reputation, an investment that is mostly lost when they go off to separate colleges and jobs. A more adaptive response to the modern world would be to more ignore wider social reprisal when very young and turbulent, then pay it more attention at a middle age of moderate turbulence, and then less attention again when old.

Let me also note that for some kinds of behavior young people can be at an endgame. Warring drug dealers who don’t expect to live more than a decade longer may feel they are in a local endgame. Also, evolution might have primed young men trying to impregnate young women while they are still promiscuous and fertile to treat that part of their lives as an endgame, since the consequences can be so huge there compared to later opportunities.

This whole perspective suggests another explanation for the puzzle of why we express more interest in people who have the potential to achieve X, relative to people who have already achieved X. Perhaps we presume that someone with the potential to X is younger with a wider social network that we might join by affiliating with them. In contrast, we presume that a person who has already achieved X is older, more tied to their key social network, and less open to new alliances with us.