<P> Cognitive scientist Herbert A. Simon originally proposed that human judgments are limited by available information, time constraints, and cognitive limitations, calling this bounded rationality . In the early 1970s, psychologists Amos Tversky and Daniel Kahneman demonstrated three heuristics that underlie a wide range of intuitive judgments . These findings set in motion the heuristics and biases research program, which studies how people make real - world judgments and the conditions under which those judgments are unreliable . This research challenged the idea that human beings are rational actors, but provided a theory of information processing to explain how people make estimates or choices . This research, which first gained worldwide attention in 1974 with the Science paper "Judgment Under Uncertainty: Heuristics and Biases", has guided almost all current theories of decision - making, and although the originally proposed heuristics have been challenged in the further debate, this research program has changed the field by permanently setting the research questions . </P> <P> This heuristics - and - biases tradition has been criticised by Gerd Gigerenzer and others for being too focused on how heuristics lead to errors . The critics argue that heuristics can be seen as rational in an underlying sense . According to this perspective, heuristics are good enough for most purposes without being too demanding on the brain's resources . Another theoretical perspective sees heuristics as fully rational in that they are rapid, can be made without full information and can be as accurate as more complicated procedures . By understanding the role of heuristics in human psychology, marketers and other persuaders can influence decisions, such as the prices people pay for goods or the quantity they buy . </P> <P> In their initial research, Tversky and Kahneman proposed three heuristics--availability, representativeness, and anchoring and adjustment . Subsequent work has identified many more . Heuristics that underlie judgment are called "judgment heuristics". Another type, called "evaluation heuristics", are used to judge the desirability of possible choices . </P> <P> In psychology, availability is the ease with which a particular idea can be brought to mind . When people estimate how likely or how frequent an event is on the basis of its availability, they are using the availability heuristic . When an infrequent event can be brought easily and vividly to mind, people tend to overestimate its likelihood . For example, people overestimate their likelihood of dying in a dramatic event such as a tornado or terrorism . Dramatic, violent deaths are usually more highly publicised and therefore have a higher availability . On the other hand, common but mundane events are hard to bring to mind, so their likelihoods tend to be underestimated . These include deaths from suicides, strokes, and diabetes . This heuristic is one of the reasons why people are more easily swayed by a single, vivid story than by a large body of statistical evidence . It may also play a role in the appeal of lotteries: to someone buying a ticket, the well - publicised, jubilant winners are more available than the millions of people who have won nothing . </P>

Which method of adding value to a product is purely psychological