Anchoring research helps clarify the question of whether to make the first offer in a negotiation: by making the first offer, you will anchor the negotiation in your favor. In fact, Mussweiler and I have shown that making the first offer affords a bargaining advantage. In our studies, we found that the final outcome of a negotiation is affected by whether the buyer or the seller makes the first offer. Specifically, when a seller makes the first offer, the final settlement price tends to be higher than when the buyer makes the first offer.
http://hbswk.hbs.edu/archive/4302.html
http://en.wikipedia.org/wiki/Anchoring
The whole article could use a lot more science. I suggest reading "59 Seconds" from Richard Wiseman.