We tend to judge the likelihood and significance of things based on how easily they come to mind. The more “available” a piece of information is to us, the more important it seems. 

The result is that we give greater weight to information we learned recently because a news article you read last night comes to mind easier than a science class you took years ago. We also give greater weight to information that is shocking or unusual. Shark attacks and plane crashes strike us more than accidental drowning or car accidents, so we overestimate their odds.

There’s a reason why cultures around the world teach important life lessons and values through fables, fairy tales, myths, proverbs, and stories.

There is no real link between how memorable something is and how likely it is to happen. In fact, the opposite is often true. Unusual events stand out more and receive more attention than commonplace ones. As a result, the availability heuristic skews our perception of risks in two key ways:

We overestimate the likelihood of unlikely events. And we underestimate the likelihood of likely events.

• Always consider base rates when making judgments about probability.
• Whenever possible, base your judgments on trends and patterns—the longer term, the better.
• Take the time to think before making a judgment. Stop and go through the relevant information, rather than assuming whatever comes to mind first is correct.
• Don’t rely on memory. Keep track of information you might need to use in a judgment far off in the future.
• Go back and revisit old information.