"…several different groups of bilinguals were more immune to common cognitive biases when making decisions in their second languages than in their native tongues."
I just read this blurb on one of my favorite languagenerdblogs, nerdily titled Language Log. There's more to it, which you can read here and here.
This certainly is my experience-I am much less likely to fly off the handle when I'm living in one of my other languages. I blogged about that a while back here. The time lag between brain and mouth in my other languages helps me self edit (and has made me think more than once that I should just give up speaking English and stick with Spanish or mmmbellymay or something.) More than that, though, words just don't get to my gut the same way if they're not in English.