Great question, no idea who are the exact people behind this (just found this online), but according to http://www.darpa.mil/tag-list?tt=73&PP=2 some interesting folks joined them recently (after 2013):
Dr. Reza Ghanadan (Defense Sciences Office (DSO), Program Manager – interests: data analytics, autonomy, machine learning and artificial intelligence in information and cyber-physical systems)
http://www.darpa.mil/staff/dr-reza-ghanadan
Dr. Paul Cohen (Information Innovation Office (I2O), Program Manager - interests: artificial intelligence, machine learning)
http://www.darpa.mil/staff/dr-paul-cohen
The contact listed in the document (http://www.darpa.mil/staff/mr-david-gunning) used to work for PARC and ran the PAL (Siri) program.