That bilingual trolley-problem study surprises me! What an interesting finding. But I guess I shouldn't have been too surprised. I have long noticed a difference in myself when thinking/speaking/interacting in French compared to in English.

I'm wondering about the study's definition of bilingual. I learned French as an adult, and while I am very comfortable reading and speaking French, often (for example) enjoying French-language films without subtitles, my French is by no means at the proficiency level of somebody who acquired a language from birth.

So I don't know if I truly qualify as bilingual.

Now, my foster son in Montreal on the other hand ...

When my partner and I were raising him, he and his friends, whether they were technically anglophones or technically francophones, switched seamlessly between languages — fluidly and without even seeming to think about it. They code switched constantly, sometimes including both languages in one single sentence or expression, apparently based on whichever language worked best for what they were trying to express.

I'm wondering if that kind of from-birth bilingualism is more what the study is referring to, as opposed to my acquired, not-quite-as-capable bilingualism.