Without going into the scientific detail here, one famous persuasion technique involves asking someone whom you suspect to be disinclined to you and your views for a favour. The psychology is that when they acquiesce, they mysteriously switch to inclination towards you.
I was reminded of a sibling of this approach over a recent series of meetings with financier execs. Every successful solution seller learns that every time you meet someone anew, a great technique is to ask them to do something for you as soon as they leave the room.
The most common request nowadays asks them to email something your way. A forwarded mail, pdf, presentation, the point is whether, and to a lesser extent how, they comply uncovers their true leanings.
The selection of the doc does matter. Not only must it be of relevance to your ambitions, but it also needs to be framed in a way that shows it’ll help your prospect (rather than selfishly just you). The more the person across the table infers it’s all about you, the less likely they are to produce the goods.