Confirmation and Motivated-Reasoning Biases

Groups the phenomena of the psychology atlas whose central finding concerns how a prior belief, a desired conclusion or an existing commitment distorts how new information or evidence is gathered, weighted or remembered, a literature most associated with Peter Wason's 1960 confirmation-bias experiments and Ziva Kunda's 1990 motivated-reasoning synthesis. Belongs here: the Confirmation Bias itself, the tendency to search for, interpret and recall information that confirms a prior belief; the Belief Bias and Belief Perseverance, judging an argument's validity by whether its conclusion is already believed, and holding onto a belief even after the evidence that produced it is discredited; the Congruence Bias, testing a hypothesis only by direct confirmation rather than by seeking evidence that could disconfirm it; the Backfire Effect, a discredited belief strengthening rather than weakening when confronted with correcting evidence, and the Semmelweis Reflex, the reflexive rejection of new evidence because it contradicts an established view; Motivated Reasoning, reasoning that arrives at a conclusion the reasoner is independently motivated to reach; Selective Perception and Subjective Validation, attending to and accepting information in a way that supports what one already wants to be true, including reading a vague statement as personally accurate; Cherry Picking, presenting only the evidence that supports a position while omitting evidence that does not; the Conservatism Bias, under-revising a belief in light of new evidence relative to a normatively correct update; the Choice-Supportive Bias, remembering one's own past choices as better than they were; the Experimenter's Bias and the Subject-Expectancy Effect, an experimenter's or a participant's own expectation about a study's result distorting the data the study actually produces; the Barnum Effect, accepting a vague, generic personality description as uniquely accurate because one already wants it to be true of oneself; and Wishful Thinking, forming a belief because it is pleasant to hold rather than because the evidence supports it. Every entry here concerns a distortion driven by an existing belief, desire or commitment shaping how evidence is treated; a distortion in judging one's own ability or future states is filed under overconfidence and self-assessment biases instead, and every other decision or judgment bias not yet split into a dedicated subcategory stays under decision-making and judgment biases.