Students received critical comments on an essay with one of two notes. A neutral note simply said the comments were feedback. The other said the teacher had high expectations and believed the student could meet them.
Among students who had most reason to doubt their teachers’ intentions, revision rates jumped from 17% to 71%.
Criticism without a stated motive is ambiguous, and people fill the gap with whatever they already fear. Naming your motive — high standards plus belief — removes the ambiguity. It costs nothing and helps most where trust is lowest.