availability heuristic

Meaning: A heuristic is a quick rule of thumb that usually works but can produce systematic errors. In the availability heuristic, ease of retrieval from memory stands in for probability or frequency. Events that are recent, vivid, emotionally charged or heavily covered by the media come to mind quickly, so they feel more common than they really are. Because common events are often easier to recall, the shortcut is frequently right, but it misleads when memory is skewed by vividness or publicity. The idea is tied to Tversky and Kahneman.

On the MCAT: A passage describes people estimating risk after news coverage, such as fearing plane crashes or shark attacks after a widely reported event while underestimating car accidents. The question asks which cognitive process explains the misjudgment. Expect answer choices that include the representativeness heuristic, confirmation bias and base-rate neglect. You may also be asked to predict a change: if media coverage of a rare event increases, people's estimates of its frequency tend to rise.

Common confusion: Students mix this up with the representativeness heuristic. Availability asks, "How easily can I think of examples?" Representativeness asks, "How closely does this match my prototype of the category?" Availability depends on ease of recall, not on how accurate the remembered information is, and it is not the same as confirmation bias, which is a search for supporting evidence.