My anecdotal experience says just having the ability to verbalize in different languages(3 in my case) makes you reason for a longer time. I suspect, that helps avoid some sort of biases, but might be a crippling factor in some situations(time-constrained decisions) .
In this case the experiment compared bilinguals who had the problem presented to them in their native tongue with bilinguals who had the problem presented to them in their second language. It found that answers were dependant on the language they had been presented in - when the answers were in a foreign language there was less decision bias. It seems that being bilingual did not prevent people from having this bias in their native tongue.
Yep, read the paper. But am very uncomfortable calling this a decision bias. It's more specific than that. It's about aversion of risk and how framing a decision in loss terms vs gain terms leads people to decide differently(see https://en.wikipedia.org/wiki/Anchoring). Otherwise i agree the bilingual subjects do display the bias in their native tongue. Am gonna try reasoning in all three languages i know and see how that affects my decision making :-P
