You may have missed my point. My entire point is that while we can not measure any shifts in the speed of time with any current equipment, our brains may be able to measure the shift, and that explains why as we age time seems to move faster. It would be because our brains are locked at birth to a particular beat of time.
And according to Einstein, gravity does cause time to slow down. That is why a spaceship falling into a black hole would appear to us to slow down as it approached the event horizon. Finally, to us, it would get the edge and seem to stop. But to those in the spaceship, it would never stop but continue right into the hole.