But in this context, it turned out that the exact opposite occurred. Expressing doubt about a contentious issue actually increased persuasion. Particularly among people who already had strong beliefs, hearing someone else wasn’t sure about their opinion encouraged them to change their mind in that direction.

The key is asking a related question that shows interest. Signaling that we are seeking relevant information rather than hiding it.

Questions like “What problems does it have?” do exactly that. Rather than implicitly assuming no issues, they assume there are some and want to root them out.

Indeed, when a third set of potential buyers asked “What problems does it have?,” potential sellers were much more forthcoming. Even though positive and negative assumption questions both directly asked about problems, negative assumption questions led sellers to be 50 percent more likely to fess up that problems could exist.

Questions not only solicit information, they reveal it. They reveal information about our knowledge, our assumptions, and even how assertive we’re going to be.

But it’s not enough just to be direct. We have to be direct in a way that not only shows that we’re aware that there could be negative information, but that we are assertive enough to keep looking for it until we find it.