The Harvard principles of negotiation are based on four principles, not rules. Because rules are more strict and linear on the contrary principles are more organic. The first principle is “separate the person from the issue” which means “do not pay attention to the person you like or you do not like”. The second principle is “negotiate not to position focused but interest-oriented”.
The pumpkin example is explained for the second principle. There are three people who want to have a pumpkin but it is impossible to give one pumpkin to the three people. So we must understand their interest. One of them might be interested in Halloween day, one might need seeds and one might want to cook. There can be found a solution for all. In this example, the most important thing to understand their interest is to ask the right questions. The third principle is “develop a criteria set to fulfill the solution”, in other words, what condition is the best for a good solution”. Just assume that you are hiring a new graduate as an HR Staff and you will place him/her in the assurance department and or audit department. So you can ask a set of questions to understand which option is the best for him or the company. The fourth one is “develop several options to choose from”. In this case, match the criteria by your options and choose the best option that matches your criteria”.
Reference: Harvard Principle of Negotiation