Cognitive biases are systematic patterns of deviation from norm and/or rationality in judgment. They are often studied in psychology, sociology and behavioral economics.
Although the reality of most of these biases is confirmed by reproducible research, there are often controversies about how to classify these biases or how to explain them. Several theoretical causes are known for some cognitive biases, which provides a classification of biases by their common generative mechanism (such as noisy information-processing). Gerd Gigerenzer has criticized the framing of cognitive biases as errors in judgment, and favors interpreting them as arising from rational deviations from logical thought.
Explanations include information-processing rules (i.e., mental shortcuts), called heuristics, that the brain uses to produce decisions or judgments. Biases have a variety of forms and appear as cognitive ("cold") bias, such as mental noise, or motivational ("hot") bias, such as when beliefs are distorted by wishful thinking. Both effects can be present at the same time.
There are also controversies over some of these biases as to whether they count as useless or irrational, or whether they result in useful attitudes or behavior. For example, when getting to know others, people tend to ask leading questions which seem biased towards confirming their assumptions about the person. However, this kind of confirmation bias has also been argued to be an example of social skill; a way to establish a connection with the other person.
Although this research overwhelmingly involves human subjects, some findings that demonstrate bias have been found in non-human animals as well. For example, loss aversion has been shown in monkeys and hyperbolic discounting has been observed in rats, pigeons, and monkeys.
Belief, decision-making and behavioral
These biases affect belief formation, reasoning processes, business and economic decisions, and human behavior in general.
Anchoring bias
The anchoring bias, or focalism, is the tendency to rely too heavily—to "anchor"—on one trait or piece of information when making decisions (usually the first piece of information acquired on that subject). Anchoring bias includes or involves the following: Common source bias, the tendency to combine or compare research studies from the same source, or from sources that use the same methodologies or data. Conservatism bias, the tendency to insufficiently revise one's belief when presented with new evidence. Functional fixedness, a tendency limiting a person to using an object only in the way it is traditionally used. Law of the instrument, an over-reliance on a familiar tool or methods, ignoring or under-valuing alternative approaches. "If all you have is a hammer, everything looks like a nail."
Apophenia
The tendency to perceive meaningful connections between unrelated things. The following are types of apophenia: Clustering illusion, the tendency to overestimate the importance of small runs, streaks, or clusters in large samples of random data (that is, seeing phantom patterns). Illusory correlation, a tendency to inaccurately perceive a relationship between two unrelated events. Pareidolia, a tendency to perceive a vague and random stimulus (often an image or sound) as significant, e.g., seeing images of animals or faces in clouds, the man in the Moon, and hearing non-existent hidden messages on records played in reverse.
