承诺升级是一种行为模式，指称当某个体或团体面对日益增高的负面结果，反而会持续合理化既存的决策、动作和投资的现象，而非改变它们。

这种行为模式的本质在于沉没成本谬误，此谬误被经济学者和行为科学家用来描述，当人们证实先前累积的投资额（沉没成本）都已经浪费掉了，反而会因为觉得过去已经投入而且不能回收的成本很「浪费」，因而做出不理性的选择，比如说当消费者发现电影票不能退费时，很多人会强迫自己看一场根本不想看的电影，因为他们怕浪费了买票的钱。

这个词被广泛用在心理学和社会学之中，也有被用来描述军事冲突的行为，例如发生在1960至1970年代的越战，美国找理由继续参战，以求可以借由胜仗来挽回已经花费的预算与人命损失。

Escalation of commitment refers to a pattern of behavior in which an individual or group will continue to rationalize their decisions, actions, and investments when faced with increasingly negative outcomes rather than alter their course. The related term sunk cost fallacy has been used by economists and behavioral scientists to describe the phenomenon where people justify increased investment of money, time, lives, etc. in a decision, based on the cumulative prior investment ("sunk costs"), despite new evidence suggesting that the cost, beginning immediately, of continuing the decision outweighs the expected benefit. These decisions are irrational in their current context but in alignment with decisions and actions previously made, and they can be influenced by a variety of determinants and contexts. The dilemmas leading up to such decisions usually involve the prior choices no longer working or causing personal or group losses. While there are options to either cease current actions or continue on with them, neither has clear outcomes or is the obvious choice. Escalation of commitment then occurs when persistence is chosen over withdrawal.