Escalation is the sunk-cost-fallacy turned into a spiral. The first addition is defended by the first loss, the second by the first two, and by the fourth the position is far larger than anything you would have opened deliberately.
It applies beyond positions. Traders escalate into strategies that have stopped working, into expensive tooling that has not paid for itself, and into a full-time trading attempt long after the evidence suggested part-time.
The way out is to separate the decision from its history. Ask what a new arrival with your capital would do today. If the answer is not what you are doing, the difference is escalation, not conviction.
Related: sunk-cost-fallacy, adding-to-losers, belief-perseverance, status-quo-bias