Zero-sum bias

Zero-sum bias is a way of thinking that says if someone is winning, someone else must be losing. This way of thinking ignores the possibility of both people winning at the same time. For example, if your friend asked you to play a game like tic-tac-toe, you might think that one of you will end up winning while the other person will end up losing. This is an example of zero-sum bias because it's not true that one person always has to win and one person always has to lose - you and your friend could both be winners if you draw!