I think that all of us would be willing to admit that we don’t know  everything. 

When it comes to a negotiation, if we’ve never negotiated  with the other side before, we understand that it would be wise to go have a talk with someone who has negotiated with them before. When we consult with others on our upcoming negotiations, we are going to have to weigh their advice against our own opinions and research. 

Research finds that all too  often we tend to undervalue advice from others and overvalue our own  point of view, even when we’re inexperienced at the task at hand.