politics- get more resources an hour. or if ur losing food u lose less food. also its faster building buildings.

attack- your troops can kill more of the enemies troops. also its makes it faster to train troops.

intelligence-faster at reseaching things. ive heard that if u use a high intelligence hero ona scout. u get more info then u normally would. im not sure though. so if anyone that knows, it would help him to confirm or decline that.