Bilingual Decision-Making and Risk
Wired has a pretty good write-up on the research, but unfortunately it doesn't talk about the fluency of the study subjects or other details. I always try to go to the primary source when it comes to summarized research, but unfortunately in this case, the full article is behind a pay-wall (don't get me started about companies that monetize academic research that has been paid for by government funding or tax dollars). A little Googling did find the complete article here, though. It's an interesting read and points out the study groups didn't even have a high level of fluency in the second languages.
This is a pretty slick brain hack worth investigating. Give it a try sometime...