Availability heuristic
[4] In the late 1960s and early 1970s, Amos Tversky and Daniel Kahneman began work on a series of papers examining "heuristic and biases" used in judgment under uncertainty.
Kahneman and Tversky explained that judgment under uncertainty often relies on a limited number of simplifying heuristics rather than extensive algorithmic processing.
This research questioned the descriptive adequacy of idealized models of judgment, and offered insights into the cognitive processes that explained human error without invoking motivated irrationality.
[5] One simplifying strategy people may rely on is the tendency to make a judgment about the frequency of an event based on how many similar instances are brought to mind.
An availability heuristic is a mental shortcut that relies on immediate examples that come to a given person's mind when evaluating a specific topic, concept, method, or decision.
Furthermore, this makes it difficult to determine whether the obtained estimates of frequency, likelihood, or typicality are based on participants' phenomenal experiences or on a biased sample of recalled information.
Tversky and Kahneman concluded that people answer questions like these by comparing the availability of the two categories and assessing how easily they can recall these instances.
[8] In Tversky and Kahneman's seminal paper, they include findings from several other studies, which also show support for the availability heuristic.
Apart from their findings in the "K" study, they also found: Many researchers have attempted to identify the psychological process which creates the availability heuristic.
Tversky and Kahneman argue that the number of examples recalled from memory is used to infer the frequency with which such instances occur.
In a study by Schwarz and colleagues to test their explanation, participants were asked to recall either six or twelve examples of their assertive or very unassertive behavior.
The researchers hypothesized that students would use the availability heuristic, based on the number of study methods they listed, to predict their grade only when asked at the beginning of the semester and about their hardest final.
The results indicated that students used the availability heuristic, based on the ease of recall of the study methods they listed, to predict their performance when asked at the beginning of the semester and about their hardest final.
If the student listed only three study methods, they predicted a higher grade at the end of the semester only on their hardest final.
The results supported this hypothesis and gave evidence to the fact that levels of uncertainty affect the use of the availability heuristic.
These results suggest that television violence does in fact have a direct causal impact on participants' social reality beliefs.
Contrary to previous research, there were no long-term effects on risk perception due to exposure to dramatic movies.
By analyzing answers to questionnaires handed out, researchers concluded that availability of AIDS information did not relate strongly to perceived risk.
[17] Participants in a 1992 study read case descriptions of hypothetical patients who varied on their sex and sexual preference.
These hypothetical patients showed symptoms that could have been caused by five different diseases (AIDS, leukemia, influenza, meningitis, or appendicitis).
To illustrate, Franklin Templeton's annual Global Investor Sentiment Survey 1 asked individuals how they believed the S&P 500 Index performed in 2009, 2010, and 2011.
In this study, Fox tests whether the difficulty of recall influences judgment, specifically with course evaluations among college students.
Students asked to do the easier evaluation with only two complaints had less difficulty in terms of availability of information, so they rated the course more harshly.
As hypothesized, respondents recalled more easily from long-term memory stories that contain severe harm, which seemed to influence their sentencing choices to make them push for harsher punishments.
To test the hypothesis, 312 university students played the roles of mock jurors and watched a videotape of a witness presenting testimony during a trial.
Subsequently, to assess what subjects could remember (as a measure of availability), each name was represented, as well as the appropriate photograph if one had been originally presented.
The study considered whether the display or non-display of photographs biased subjects' estimates as to the percentage of Yale (vs Stanford) students in the sample of men and women whose names appeared on the original list, and whether these estimated percentages were causally related to the respondents' memory for the college affiliations of the individual students on the list.
Such effects have typically been attributed to the ready accessibility of vividly presented information in memory—that is, to the availability heuristic.
Based on the possibility of explanations such as these, some researchers have claimed that the classic studies on the availability heuristic are too vague in that they fail to account for people's underlying mental processes.
Indeed, a study conducted by Wanke et al. demonstrated this scenario can occur in situations used to test the availability heuristic.
