These days, it seems like there’s more arguing over what counts as a “fact” and what counts as an “opinion” than should ever be necessary. Well, we have bad news. The trouble doesn’t start with “fake news” — it starts in your brain.

We already know that your interpretation of facts can vary wildly depending on your beliefs. Confirmation bias and the backfire effect are always going to shape the way you interact with your world. But according to a new report on a phenomenon known as involuntary opinion confirmation, you might have a hard time sorting out the facts in the first place. That’s because when your brain is exposed to an opinion it agrees with, it automatically slips it into the “facts” folder of your mental filing cabinet.

It all comes down to the Stroop effect. If the name of a color is printed in a different color…