Each side (labor union and managers) have preconceived notions about each other. Labor union leaders feel that managers are political and do not get the whole negotiating process because they are cheap. Managers feel that labor union representatives not nothing about the management process and that they know nothing about the big picture (pg. 278). In order for labor negotiations to be successful and for both sides to feel like at least most of their needs have been met, labor unions and managers need to set aside any preconceived notions and try not to be judgemental. Membership in labor unions has decreased from 32.5% of the working population in the private section in the 1950's to about 13% in 2009. The public sector has not seen such a drastic decrease, but overall this means that the number of labor negotiations has also decreased (Kersie and Cutcher-Gershenfeld, 2009). While this may be true, the union leaders must be aware that the employees may have trepidation about joining the union because they want to know what the union will do for them and management will be concerned with how the labor union will affect the organization and workers as well as other things.

Interest-based negotiations...

With traditional bargaining, both parties only seek what benefits them. There is no compromise which creates hostility. With interest-based negotiations, problem solving is used to find solutions to issues that benefit both parties. This type of bargaining promotes harmony. This type of negotiation process is concerned with the needs of both sides and not just one.
References

Berman, E.M., Bowman, J.S., West, J.P., & Wart, M.V. (2002). Unions and the Government: Protectors, Partners and Punishers. Human Resource Management in Public Service: Paradoxes, Processes, and Problems (Second Edition ed., pp. 275-303). Thousand Oaks, Calif.: Sage Publications.

Fonstad, N.O., McKersie, R.K., and Eaton, S.C. (2004). Interest-based negotiations in a transformed labor-management setting. Negotiation Journal, 20(1), 5-11.

McKersie, R. And Cutcher-Gershenfeld, J. (2009). Labor-management relations: Understanding and practicing effective negotiations. Negotiation Journal, 25(4), 499-514.