The process of generating a judgment can be simplified by using rules of thumb, which are referred to as heuristics. There are a number of heuristics that are highly general in nature and can be applied to cues that are available in a great variety of situations. In addition to such general heuristics, individuals may have evolved content-specific simplifying judgment rules. At the heart of each of these heuristics is a certain cognitive type of processing or inference. This chapter discusses three cognitive heuristics. First, it describes the availability heuristic, originally introduced as a rule of thumb to gauge frequency or probability. Second, it addresses the representativeness heuristic, which is used to assign single elements to larger categories, but is also employed to estimate frequency and probability. Third, it examines the heuristic that has been labeled "anchoring and adjustment".