Jumping to conclusions is a common type of error or fallacy in reasoning or thinking, in which a person draws conclusions which are not warranted from available information. In the language of cognitive behavioral therapy, jumping to conclusions is one of the common cognitive distortions characteristic of depression and anxiety. In depression or anxiety, a person often falsely concludes that things are going to go wrong, or that they have done something wrong. However, people can also jump to false conclusions in ways that introduce positive bias, or other sorts of bias.
When jumping to conclusions, a person skips the step of considering possible interpretations for a situation, and instead jumps right to accepting whatever interpretation seems most plausible to them. In general, when people jump to conclusions, they tend to pick interpretations that fit their own existing view of the world. Jumping to conclusions, when it becomes a chronic problem, thus tends to lead to people getting stuck in their own viewpoint, even when it does not fit with reality.