I believe....

[R'tal]

I believe that intel is affected by not only intel points spent by your empire, and intel points spent toward defense by another empire; But also by your race's natural tendency towards intel opps as dictated by racial charactweristics and culture. I us intel a lot and I'm usally about 130% on cunning which dictates intel aptitude, and use a culture with 5 or more percent on cunning.