Here’s a brilliant insight I received from a judge years ago, when I served on a jury.

Moments before our trial got underway, the judge issued the jury this warning: As you hear this case, he said, make every effort not to write a narrative in your mind of “what happened.”

“He’s guilty,” “she’s really the victim here,” “these people are all crazy and neither side deserves any money” — these are all narratives, and they’re all detrimental to a juror’s ability to fairly hear a case and weigh the evidence presented. The moment you write a narrative, you immediately and permanently become incapable of learning anything new.

The judge said he had seen this happen so many times that he could tell not only when a juror had written a narrative mid-trial but in whose favor the juror had decided. The signs: The juror would take notes in her court-provided journal only on those points that favored her position. She would pay close attention only to witnesses testifying on behalf of the party she favored. And she would appear completely disinterested in testimony that tended to undermine her narrative.

This insight has broad and valuable application for our lives. As soon as you write a narrative, it becomes your reality. So be careful.

If you’re unhappy in your career, and you tell yourself, “I’ve tried everything to find a better job,” you’ve written a narrative. You’ve told yourself you’ve exhausted all ideas and so there simply is no better job for you. So you’ll stop trying. And indeed you won’t find a better job.

Our narratives are self-fulfilling prophecies.

Anytime you say or think, “I’m not smart enough to try that” or “This party is boring,” guess what? You’ll be right.

Watch your narratives.