I think it's worth introducing to the discussion that human reaction time to an unanticipated stimulus is somewhere around 150-250ms. The ~140-150ms practically

I think it's worth introducing to the discussion that human reaction time to an unanticipated stimulus is somewhere around 150-250ms. The ~140-150ms practically achievable latency over a hemispheric arc in real world IP networks is already fairly close to the limit imposed by the human element. However, latency in IP networks is measured as RTT while human reaction time to a stimulus is given as the one way path latency. The more accurate comparison would be between the ~70ms one way path latency of the optical terrestrial network with the same 150-250ms of one way path latency for the human to react to a directly applied stimulus. At the extreme of the range of human factors and accounting for the differing scale, human factors are responsible for up to 80% of the reaction latency.