The Science of Availability

Which presidential candidate is doing more advertising this year? Which college football team has been the most dominant over the last five years? Who has had the most songs on the Hot 100 over the last five years? You can probably come up with an intuitive answer to (at least one of) these questions even if you don’t follow politics, college football, or pop music very closely. But what you are doing when you come up with an intuitive answer isn’t really answering the question, but instead relying on substitution and the availability heuristic.


In Thinking Fast and Slow, Daniel Kahneman writes, “We defined the availability heuristic as the process of judging frequency by the ease with which instances come to mind.” So if you recently saw a few ads from the Trump Campaign, then your mind would probably intuit that his campaign is doing more advertising. If you remember that LSU won the college football national championship last year, then you might have answered LSU, but also if you see lots of people wearing Alabama hats on a regular basis, you might answer Alabama. And if you recently heard a Taylor Swift song, then your intuitive guess might be that she has had the most top 100 hits.


Kahneman continues, “The availability heuristic, like other heuristics of judgment, substitutes one question for another: you wish to estimate the size of a category or the frequency of an event, but you report an impression of the ease with which instances come to mind.” When we are asked to guess how often an event happens or what percent of a category fits a certain characteristic, our brains flip back through short-term memory for examples that match what we are looking for. The easier it is to remember an example the more weight we give to it.


I don’t really know who is doing more advertising, but I do know that I have seen a lot of Trump ads on YouTube, so it intuitively felt that he was doing more advertising, even though I might have just picked one channel where his ads were more salient. Overall, he may be doing less than the Biden campaign. Similarly, I didn’t initially remember that LSU won the national championship last year, but I did see someone wearing an Alabama sweatshirt recently, and that team came to mind quickly when thinking of dominant football programs. I also don’t have a clue who has had the most top 100 hits in the last 5 years, but people in my orbit on Twitter frequently post things relating to Taylor Swift, so her name came to mind easily when guessing for the top 100 hits. I wasn’t doing any deep thinking, I was just scratching the surface of my memory for an easy answer.


Throughout Thinking Fast and Slow, Kahneman reveals instances where our thinking appears to be deep and nuanced, but is really quick, intuitive, and prone to errors. In most instances we don’t do any deep calculation or thinking, and just roll with the intuitive answer. But our intuition is often faulty, incomplete, and based on a substitution for the real question we are being asked. This might not have high stakes when it means we are inaccurately estimating divorce rates for celebrities (an example from the book), but it can have high stakes in other decision-making areas. If we are looking to buy a home and are concerned about flood risk, we will incorrectly weight the risk of a flood at a property if there were a lot of news stories about hurricane flooding from a hurricane in the Gulf of Mexico. This could influence where we chose to live and whether we pay for expensive insurance or not. Little assumptions and misperceptions can nudge us in critical directions, either positive or negative, and change whether we invest for our futures, fudge our taxes, or buy a new car. Recognizing that our brains make mistakes based on thinking strategies like the availability heuristic can help us in some large decision-making areas, so it is important to understand how our brains work, and where they can go wrong.

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