Final answer:
The availability heuristic is a mental shortcut that leads people to judge the frequency or likelihood of events based on how readily examples come to mind, which can result in a skewed perception of reality.
Step-by-step explanation:
The availability heuristic is a cognitive bias that influences people to overestimate the likelihood of events based on their availability in memory; that is, how easily they can recall these events. An example of this would be perceiving a higher risk of plane crashes after seeing a plane crash reported in the news, despite statistical evidence showing that air travel is relatively safe.
The availability heuristic causes individuals to make judgments based on how easily they can bring examples to mind, rather than on all the relevant data or statistics available. This can lead to a distorted perception of reality, as the news often reports more unusual or dramatic events, which are not necessarily the most common.
The availability heuristic does not say that two events occurring together are more likely than either event by itself - that's a misunderstanding of the concept of joint probability. Also, it is not the most accurate of the heuristics; rather, it can often lead to errors in judgment because it is based on anecdotal and not statistical evidence.