One of the sacrosanct rules of brainstorming is that criticism isn’t allowed.  Yet according to a new study from Berkeley psychology professor Charlan Nemeth and grad student Matthew Feinberg, enforcing that rule can lead to less creative sessions.

The key, according to the study, is the way in which the rule is communicated. In an earlier study, Nemeth found that encouraging debate had resulted in livelier, more productive sessions. So in this study, she set out to discover whether the no-criticism rule actually stifled creativity.

The answer?  It depends.  If the instruction is delivered as a rule, participants seem to feel constricted.  If it’s delivered as coaching or a suggestion, people feel less restricted, more able to express divergent ideas.

So, when you’re telling people to break the rules, make sure you’re not imposing another one.