Intractable conflicts, including that between Israel and West Bank and Gaza Palestinians, are perpetuated by a number of psychological and relational barriers that prevent the parties from reaching agreements that would serve the parties mutual self-interests. This article reviews the nature of and empirical evidence for the operation of several such barriers, including enmity and distrust, false polarization, dissonance reduction and collective rationalization, insistence on justice rather than mere advance on the status quo, reactive devaluation of proposals from the other side, and naïve realism, with special attention to the role they play in asymmetric conflicts such as that in the Middle East. Some research evidence suggesting strategies for overcoming these barriers and unfreezing deadlocks is also discussed, along with some lessons that the author and his Stanford Center on Conflict and Negotiation have gleaned from their real-world experiences in second-track diplomacy and their efforts to promote constructive dialogue between Israelis and Palestinians, and between the rival political factions in Northern Ireland.