I think there might be some experimental data in support of the fact that (at least some types of) neurons get slower as we age, though I believe it was for met

I think there might be some experimental data in support of the fact that (at least some types of) neurons get slower as we age, though I believe it was for metabolical reasons not due to connection length. I still think you might have a good point there not only due to that cellular slow-down, but also because I would certainly expect an increase in connection density, thus leading to longer computations. I seem to recall an article from Joel on Software about the same phenomenon from a procedural point of view, where he compares increasingly complex institutional reaction times to the increasing amount of ritual that is being performed before we leave the house (with old people taking the longest time, because based on past experience of all things that went wrong in the past, their checklists before leaving the house become absurdly long over time). Just an interesting side observation about the VLC speed thing: my personal sense of rhythm has always been so bad that I couldn't tell the difference between 100% speed then and 80% speed now. But an observation I recently made was that I can now comfortably listen to videos at 110% or even 120% their speed without losing content - something I certainly couldn't do at a younger age (in fact, I remember I often had to pause recordings in order to think about stuff that just happened or even just to empty my "language recognition buffer" before I could move on). So while it may well be true that 1 second doesn't last as long for me as it used to, I certainly seem to have become more efficient at processing some types of data.