<unk>  arises from various life, loyalty and local risk and attention concerns that are difficult to separate or codify. Much of the present scientific understanding of<unk> es stems from the work of Amos Tversky and Daniel Kahneman and their colleagues, whose experiments demonstrated distinct and replicable ways in which human judgment and decision-making differ from rational choice theory. This led to Tversky and Kahneman developing prospect theory as an alternative. Tversky and Kahneman claim that the<unk> es they identified are at least partially the result of problem-solving using mental short-cuts or "heuristics", for instance using how readily or vividly something comes to mind as an indication of how often or how recently it was encountered (the availability heuristic). Other<unk> es have been demonstrated in separate experiments, such as the Confirmation<unk>  demonstrated by Peter C. Wason.
Some scientists have questioned whether all of the 'biases' are in fact errors. David Funder and Joachim Krueger have argued that some so called 'biases' may in fact be 'approximation shortcuts', which aid humans in making predictions when information is in short supply. For example, the false consensus effect may be viewed as a reasonable estimation based on a single known data point, your own opinion, instead of a false belief that other people agree with you.
Cognitive bias
Unblinding
Length time bias
Bias of an estimator
Mass effect 
Lotus effect
Attrition 
Validity 