Bias refers to an unfair tendency to prefer one thing, group, or outcome over another, often subconsciously. It affects decision-making, judgment, and perception, leading to skewed evaluations that lack objectivity. Psychologically, bias arises from heuristics, stereotypes, and past experiences. The other options describe ideal states of impartiality, objectivity, or fairness, which are the opposite of bias. Therefore, prejudice or favoritism best captures the meaning and impact of bias.