Cognitive bias refers to systematic patterns of deviation from norm or rationality in judgment. These biases can affect how we perceive information, make decisions, and interpret events. They often arise from the brain's attempt to simplify information processing, leading to errors in thinking. Common examples of cognitive bias include the confirmation bias, where individuals favor information that confirms their existing beliefs, and the anchoring effect, where people rely too heavily on the first piece of information they encounter. Understanding these biases can help improve decision-making and critical thinking skills.