Cognitive biases are systematic patterns of deviation from norm or rationality in judgment. They occur when individuals rely on subjective judgment rather than objective analysis, leading to errors in thinking. These biases can affect decision-making, perception, and memory, often resulting in illogical conclusions or misinterpretations of information. Common examples of cognitive biases include the confirmation bias, where people favor information that confirms their existing beliefs, and the anchoring effect, where individuals rely too heavily on the first piece of information encountered. Understanding these biases can help improve critical thinking and decision-making skills.