Sometimes the hardest part about talking to other people isn't finding the right words to say, but deciding if you should say anything at all. Abi Inman/NPR hide caption

Abi Inman/NPR

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Should you tell your partner how you really feel about their casserole? Offer a colleague feedback about their subpar interview performance? Let a stranger know she has toilet paper on her shoe?

Sometimes the hardest part about talking to other people isn't finding the right words to say — but deciding if you should say anything at all, says social psychologist Vanessa Bohns.

"There are times when honesty is the best policy," she says. "On the other hand, honesty is not the best policy if whatever we say is going to be honest without any instrumental value."

Bohns is the author of Should I Say Something? The Science of What to Share—and What to Keep to Yourself , published in October.…