Venkatesh Rao@vgr·Sep 13, 2014Is there a good measure of mental energy, focus and alertness? 1-3 variables that are as easy to measure as heart rate?62
Venkatesh Rao@vgrReplying to @skinnerlayne.@skinnerlayne what's the theory behind pupil diameter as a measure of alertness/energy/focus?8:40 PM · Sep 13, 2014