Availability Error
David Kyle Johnson
I’m never getting in a plane again. They’re just too dangerous. Seems like there’s another plane crash every month. From now on, I’m driving everywhere I go.
Anonymous
One commits the availability error when one pays attention to, or is compelled by, the readily available evidence - the evidence that is obvious, memorable, or psychologically compelling - instead of taking into account all the evidence or the reliable evidence. If you believe that a full moon makes people crazy (the so called “lunar effect”), and take special notice of crimes committed during full moons while ignoring the same kind of crimes on all other nights, you are subject to the availability error.
The availability error contributes to confirmation bias, the tendency to only pay attention to the evidence that confirms what you believe and ignore the evidence that doesn’t. But the error can also just appear on its own. In the quotation that begins this chapter, the person (who shall remain anonymous) is only paying attention to the stories about plane crashes she hears on the news and ignoring the statistical evidence that traveling by automobile is far more dangerous than traveling by plane. In reality, you have a 1/98 chance of dying in a vehicle accident in your lifetime, but your chances of dying in a plane crash are 1/7178. Why do people think plane travel is less safe? Because plane accidents are so rare and compelling, they get news
coverage and thus are immediately apparent to one’s mind. Traffic accidents, on the other hand, are so common we don’t even think twice about them. But the fact that they are so common is why, rationally, we should be more wary of driving to work than flying to a distant location.
The availability error also encourages other fallacies, such as hasty generalization - where you generalize about an entire group based on a statistically insignificant portion of that group.
If you conclude that all members of some race are violent criminals just because you noticed a few people of that race that are, you are paying attention to the psychologically compelling evidence (the stories about the criminals) and ignoring the better, less compelling evidence (the much larger number of people in the group who are not violent criminals).Many people try to take advantage of our propensity to commit the availability error in order to fool us. Self-professed psychics, mediums, and astrologers are great examples. Psychics take advantage of this by putting out hundreds of predictions at the beginning of the year and then only mentioning the ones they got right at the end of the year. Or consider this real-life dialogue from an astrological reading given on one of my favorite television shows, Penn & Teller’s Bullshit:
Reader: Are you living near a railroad, or a diamond store, or a government building?
Sitter: There’s a train track in front of my complex now.
Reader: Yeah, that’s the Capricorn Moon.
The reader is actually using two tricks here. One is that he is stating things that are true of almost everyone; railroads, diamond (jewelry) stores, and government buildings are everywhere, so most people live near at least one. (I currently live near all three.) But he is also counting on the reader’s focusing on what he gets right (in this case the train track) and ignoring what he doesn’t. In another part of the reading, the reader asked this same sitter whether she lived near a jungle, the woods, the country, a zoo, a church, a courthouse, a publishing house, a college, or the outdoors. She answered no to all, yet afterwards she still ranked the accuracy of the astrologer’s reading as a 10 out of 10. Why? Because of the availability error. She’s remembering the hits and forgetting the misses.
In fact, memory is especially susceptible to the availability error because we are apt to remember only what is memorable, and that is often only what is psychologically compelling.
This is why people often think they always get stuck in the slow lane in traffic jams. Think about it. When you are stuck in the slow lane, what’s it like? You’re frustrated, it’s likely to make you late, you’re there for a long time, and you’ll stew about it for hours. But when you’re in the fast lane, you’re calm, you’re not there for long, and you’ll likely forget about it a mile later. Statistically speaking, you’re in the fast lane just as often as the slow lane, but you remember being in the slow lane more often because being in the slow lane is more memorable.Or take another experience that most of us have had: being suddenly reminded of a dream you had because of some event that happened during the day. Such an event causes some people to suspect that they have psychic powers - that they can dream the future before it happens. But in reality, we should expect for such a thing to happen to us every now and again. According to Ted Schick and Lewis Vaughn (2014), authors of How To Think about Weird Things, although we only experience four or five periods of REM (rapid eye movement) cycle sleep a night, we normally experience at least 250 dream themes each night (117). We of course forget most of them and thus ignore all the counter-examples that show that our dreams don’t predict the future. So when an event during the day triggers a memory of something we dreamed, it may seem remarkable - but statistically speaking it’s bound to happen every now and again.
Take the story (mentioned in chapter one of Weird Things) of someone who dreamed of not being able to save his father from falling off a cliff only to (in real life, three weeks later) fail to save his father from falling out of a second-story window to his death while painting a windowsill. This too may seem remarkable but (a) this person is failing to recall the hundreds of his dreams that didn’t come true and (b) we are failing to recognize all the people to whom this hasn’t happened.
In other words, given the large number of dreams that are had every night and the large number of accidents that happen to people during the day, “premonitions” such as this are statistically likely.
Just about every day someone, somewhere, has a dream at night about an accident and then experiences or is reminded of a similar accident during the day. It may be unlikely to happen to any particular individual, but it is likely to happen to someone - no supernatural powers required.But this is not the only way that memory can lead us astray. In fact, memory is notoriously unreliable - much less reliable than people assume. We think of memory as being like a video camera, able to record events and play them back just as they happened (see Maynes2011). In reality, the process of storing and recalling memories is highly unreliable and apt to failure. When we store a memory of an event, we don’t record all the specifics. We store general themes and leave out the details. When we recall that event, we harken back to the theme but fill in the details according to what might make sense - or even to what would make the memory align with our expectations. When we store the memory away again, some of those confabulated details can be stored away with it. And the next time we recall that event, we are not remembering the first time it happened but the last time we remembered it (see McDermott and Roedifer n.d.). Consequently, those confabulated details can seem just as accurate as things that actually happened.
Worse still, the more often you remember something, the less accurate the memory becomes; every time you remember, you create a new opportunity for something to go wrong in the memory process (see Fernyhough 2014). This is why, when you go back and watch a movie you only saw once but haven’t seen in a while, individual scenes (or even major plots points) are often very different than you remembered them being the first time.
In fact, recent research into memory has shown that eyewitness testimony - which was once thought to be one of the most reliable methods for gathering evidence in the courtroom - is notoriously unreliable (see Arkowitz and Lileinfeld 2010).
Indeed, it’s often the case that the more confident an eyewitness is that their memory accurately reflects what happens, the less likely it is that it actually does (see Crowell 2011). We all think we can justifiably believe that something happened if we saw it with our own eyes, yet the research suggests that far more often than we realize, our memory of what we have seen with our own eyes is not accurate.Even memories of large events - so called “flashbulb memories,” like your memory of where you were when you heard about 9/11 - aren’t as reliable as we assume. Now they do seem especially clear and vivid, and we do recall them with confidence. But in one study, led by New York University psychologist W. Hirst (2009), researchers asked and recorded the details of where people were, what they were doing, and whom they were with when they first heard of the 9/11 attacks. When they followed up with the same people one year later, their memories were only 63% accurate. After three, they were down to 57%!
This wasn’t a fluke. Many such studies have been done and they all show basically the same thing. To be fair, it seems that most of the confabulating and forgetting that will be done has been done after three years. The flashbulb memories of 9/11 weren’t that much less accurate 10 years out (see Law 2011). But still, 57% is much less accurate than most assume our flashbulb memories to be. In fact, that’s probably less reliable than you assumed your normal memories to be.
All in all, we make the availability error simply because we are prone to. Of course we pay attention to what is more psychologically compelling - that’s what “psychologically compelling” means. Of course we remember what is most memorable - that’s what “most memorable” means. But if we want avoid being led astray—into believing that which is false—we must be aware of the availability error and strive to avoid it.
References
Arkowitz, Hal, and Scott O. Lilienfeld. 2010. “Why Science Tells Us Not to Rely on Eyewitness Accounts.” Scientific American Mind, January 1.
http://www. scientificamerican.com/article/do-the-eyes-have-it (accessed September 25, 2017).Crowell, Jeremiah, dir. 2011. “Brain Games: Remember This!” Brain Games, National Geographic, October 9.
Fernyhough, Charles. 2014. Pieces of Light: How the New Science of Memory Illuminates the Stories We Tell about Our Pasts. New York, NY: Harper Perennial. Hirst, W., E.A. Phelps, R.L. Buckner, A.E. Budson, A. Cuc et al. “Long-term Memory for the Terrorist Attack of September 11: Flashbulb Memories, Event Memories, and the Factors That Influence Their Retention.” National Center for Biotechnology Information. U.S. National Library of Medicine, May 2009. http://www.ncbi.nlm. nih.gov/pubmed/19397377 (accessed September 25, 2017).
Maynes, Andrew. 2011. “Memory Is Not as Reliable as We Think.” Meeting of The British Psychological Society, September 8, 2011. University of Keele, Newcastle-under-Lyme.
Law, Bridget Murray. 2011. “Seared in Our Memories.” American Psychological Association, September 15. http://www.apa.org/monitor/2011/09/memories.aspx (accessed September 25, 2017).
McDermott, Kathleen B., and Henry L. Roedifer. n.d. “Memory (Encoding, Storage, Retrieval).” Noba. http://nobaproject.com/modules/memory-encoding-storage- retrieval (accessed September 25, 2017).
Schick, Theodore, and Lewis Vaughn. 2014. How to Think about Weird Things: Critical Thinking for a New Age. New York, NY: McGraw-Hill.