Only by understanding the interests of the counterparty can a negotiator work to develop options that are going to meet everyone’s needs. One can learn these interests indirectly, through the application of logic, and through direct communication. The best way to learn of the other’s interests is from what they say. The degree of disclosure by the other party will be influenced by the tone at the bargaining table.
Set a Tone Conducive to Candid Disclosure; Be Effective as an Active Listener.