For me, it for sure is the brain.
I am always trying to create lots of possible outcomes from the decision. So maybe the heart will put some ideas forward but the brain makes the end call!
Regardless which one takes the decision, we should never regret it. We should learn from it, so that the next decision will be easier or at least not so stupid :)
Cheers,
Peter
If your heart put some ideas and brain makes decision, there is balance. Problem is when your heart doesn't agree with your brain's ideas :-)