I'm looking for a word or a phrase to describe a particular aspect of negotiations. This concept is not unique to negotiations, but negotiations seem to provide the clearest example. The concept is this: The more you ask for, the less likely you are to succeed. There is an inverse relationship between the probability of you getting a good outcome, and how high you set your definition of "good outcome."
If we imagine a simple scenario in which an employee and a boss are negotiating a salary between 0 and 10, if the employee asks for 9 she immediately loses goodwill, as well as loses the respect of the boss. It is very unlikely that she will receive 9. But if the employee asks for 6 (a more 'reasonable' number) her chance of receiving 6 is much higher.