The Availability Heuristic

This principle sates that basing the estimated probability of an event on the ease with which relevant instances come to mind. My friend Robert has believed this principle throughout his teenage years. He smokes about a pack of cigarettes a day. But he believes that smoking that much will not affect his health at all, because his grandmother smoked three packs a day since she was fourteen and is still perfectly healthy at the age of seventy. He believes the availability heuristic because his grandmother is an available source that shows that smoking does not affect her health at all, so he believes what is available to him instead of the statistics that he is told.