It is surprising that the exact mechanism of this behavior is not known. It must be related to habits. To the microbiome where most of our decisions are made. Would like to know more about how to leave out the conscious mind. I notice that when I'm doing a task on the computer which is interestingly repetitive that requires some dexterity I forget about the passage of time. So one can achieve this state even in daily life that does not require the return of a tennis ball under stress.
It seems that our logical side evolved to predict behaviors of others since empathy is limited to same species. It is probably the other side of the same circuit...
Similar to how A3C ANNs work, we have a reflective capability to change how and what we're training. "Superego" so to speak. A metric ton of automated systems for learning and action though.
At least two action oriented predictors - logical/heuristic and direct emapthic/sympathetic.
As to not noticing passage of time consciously, it is because conscious though likely it's more energy intensive, so to save it when subconscious processes are sufficient it gets throttled down. Of course this is a "just so" explanation and we do not actually know how exactly this works. Perhaps the consciousness related to sensing time and rhythm gets relegated to something else.
I believe loaded words like "subconscious" make it difficult to come up with new explanations.
It's interesting that when the body is happy and relaxed the mind is not aware of it. So there seems to be a continuous struggle between the ordering mind and instinctive body. Or the mind and the animal side.
The contentment might be like temperature in an annealing system or experimentation/forgetting tunable in an artificial system.
When we're content, nothing has to be changed, right? The trouble is, our "contentment sensor" has been evolved a long time ago for a different environment and is probably hard to train being so ancient and we do not know how to do it...
Of course this is another "just so" explanation. There's not enough science on contentment and discontent related to intellectual performance.
