 Availability can be influenced by the emotional power of examples and by their perceived frequency; while personal, first-hand incidents are more available than those that happened to others, availability can be skewed by the media.In his book Thinking, Fast and Slow, Kahneman cites the examples of celebrity divorces and airplane crashes; both are more often reported by the media, and thus tend to be exaggerated in perceived frequency.An important class of judgments is those concerning risk