Primary Psychological Heuristics
Decision Shortcuts that Bias Humans' Perception and Judgment
Aug 25, 2008
Heuristics are informal methods of problem solving – strategies that are easy and quick, but can produce a myriad of errors and biases in reasoning. The three major heuristics identified by Nobel laureate Daniel Kahneman and Amos Tversky (1974) in the journal Science are representativeness, availability, and anchoring-and-adjustment.
Representativeness Heuristic
The representativeness heuristic explains biases related to statistical probabilities. In Tversky & Kahneman’s (1974) seminal paper, they associated the representativeness heuristics with biases related to base-rates, sample sizes, regression to the mean, and the gambler’s fallacy. Individuals estimate the probabilities that apply to a specific situation based on the degree to which it is representative of a known category. That is, when making likelihood judgments, people rely on an item’s similarity to the prototypes of existing categories.
For example, when judging the probability that Joanna is an actress, individuals first decide how representative she is of typical actresses. If Joanna is dramatic and histrionic, stereotypical qualities for actresses, people typically report that she is more likely to be an actress than a waitress, regardless of the base rates of actresses and waitresses (even if the employment categories were not confounded by extreme overlap -- many actresses are also waitresses). Further, conducting a biased search of their knowledge of Joanna when testing the hypothesis “Joanna is an actress” can lead individuals to recall her congruent personality traits more than her incongruent personality traits (for example, she may be nervous in front of large groups of people).
This heuristic explains many of the biases in stereotypes and prejudice research. Recent work in “infrahumanization” suggests that individuals view members of their ingroup as more human, and more capable of experiencing human emotions than outgroup members.
Availability Heuristic
The availability heuristic explains errors based on biased memory retrieval. Probabilities are judged based on the ease of recall from long-term memory. Scientists assume that events recalled more quickly and easily are likely to have occurred more frequently in the past, and are thus more likely to occur in the future. Reliance on this heuristic can result in biases when one’s exposure to reality is biased, both by personal experience and media coverage.
In social cognition, this heuristic explains the fundamental attribution error, as well as cultural centrism. For example, undergraduate students in a global sociology course underestimate the proportion of migrant workers worldwide, given that they are middle-class white US college students and have oversampled from their ingroup when accessing their memory for migrant workers.
Anchoring-and-adjustment Heuristic
The anchoring-and-adjustment heuristic at first appears to be a special case of the availability heuristic; the initial anchor retrieved from memory or provided in the problem determines the range of potential responses. When using the anchoring-and-adjustment heuristic, individuals make judgments by anchoring on an initial value and adjusting their answer from that point. Individuals’ estimates of price, quantity, distance, and likelihood can be altered drastically by manipulating the initial value.
This heuristic produces biases in identifying confidence intervals and insufficient adjustments. By providing the initial anchor when framing a problem, researchers and pollsters can influence the judgments and decisions they obtain.
The anchoring-and-adjustment heuristic explains many social comparison biases as well as framing effects in person perception. Use of the anchoring-and-adjustment when the anchors are self-generated implies a dual-process model in which individuals use the controlled, explicit process of adjusting from an automatic, implicit anchor.
Further reading
T. Gilovich, D. Griffin, & D. Kahneman (Eds.) Heuristics and Biases: The Psychology of Intuitive Judgment. New York, NY: Cambridge University Press.
 |
