I've written in the past that one of the secrets to negotiating with partners or potential partners is to always communicate the reasons behind your position. It's critical. The partner doesn't have to agree with your position, but you must explain the business logic behind it. People don't like things that don't make sense. With this in mind, I came across an interesting phenomenon called the "Photocopier Effect" in a Malcolm Gladwell New Yorker article from a while back. The Photocopier Effect proves, scientifically, why it's so important to emphasize the reasons behind your position. From the column:

...Harvard social scientist Ellen Langer. Langer examined the apparently common-sense idea that if you are trying to persuade someone to do something for you, you are always better off if you provide a reason.

She went up to a group of people waiting in line to use a library copying machine and said, "Excuse me, I have five pages. May I use the Xerox machine?" Sixty per cent said yes.

Then she repeated the experiment on another group, except that she changed her request to "Excuse me, I have five pages. May I use the Xerox machine, because I'm in a rush?" Ninety-four per cent said yes.

This much sounds like common sense: if you say, "because I'm in a rush"--if you explain your need--people are willing to step aside.

But here's where the study gets interesting. Langer then did the experiment a third time, in this case replacing the specific reason with a statement of the obvious: "Excuse me, I have five pages. May I use the Xerox machine, because I have to make some copies?" The percentage who let her do so this time was almost exactly the same as the one in the previous round--ninety-three per cent.

The key to getting people to say yes, in other words, wasn't the explanation "because I'm in a rush" but merely the use of the word "because." What mattered wasn't the substance of the explanation but merely the rhetorical form--the conjunctional footprint--of an explanation.