In psychology, a heuristic is an easy-to-compute procedure or rule of thumb that people use when forming beliefs, judgments or decisions.
Individuals automatically assume that their previous behavior will yield the same results when a similar situation arises.
For example, after a situation occurs for the first time, you begin to notice it when it reoccurs and therefore because you have now experienced it, it's more readily available in your consciousness and you pull information and predict aspects of the future because of this and think that you "knew it all along."
Recent studies have used functional magnetic resonance imaging (fMRI) to demonstrate that people use different areas of the brain when reasoning about familiar and unfamiliar situations.
These two similar but dissociated processes provide a biological explanation for the differences between heuristic reasoning and formal logic.
The result of this study was that the subjects were more familiar when the face was attractive regardless of prior exposure to the picture (or person) itself.
Due to the familiarity heuristic, the customers have the rule of thumb that their past behavior of buying this specific brand's product was most likely correct and should be repeated.
Lay people tend to make health decisions that are based on familiarity and availability as opposed to factual knowledge about diseases.
This means that they are more likely to take actions and pursue treatment options that have worked in the past, whether they are effective in the current situation or not.
For example, a lay person may request a name-brand medication because they have heard of it before, even though a generic drug may be essentially the same but less expensive.
[8] However, in order for a heuristic to be valid, its effect should be more prevalent when individuals are distracted and their cognitive capacity is highly strained.