When it comes to the availability heuristic, fluency seems to be the most important factor. The ease with which an example of something comes to mind matters more than the real world frequency of the event. Salient examples of people being pulled over by the police, of celebrity divorces, or of wildfires cause our brains to consider these types of events to be more common and likely than they really are.
In Thinking Fast and Slow, Daniel Kahneman shares results from a study by German psychologist Norbert Schwarz which demonstrates fluency versus frequency in our analysis of the world. Schwarz asked participants to list six instances in which they behaved assertively, and to then rate their overall level of assertiveness. In a second instance, Schwarz asked participants to list twelve instances where they were assertive and to then rate their overall level of assertiveness. What the studies show is that those who were asked to come up with 6 instances of assertiveness considered themselves to be more assertive than those asked to come up with 12 instances. Kahneman describes the results by writing, “Self-ratings were dominated by the ease with which examples had come to mind. The experience of fluent retrieval of instances trumped the number retrieved.”
The logical expectation would be that asking people to list 12 instances of assertiveness would give people more reason to believe they were a more assertive person. However, that is not what the study showed. Instead, what Kahneman explains happened is that as you are asked to pull more examples from memory, your brain has a harder time remembering times when you were assertive. You easily remember a few stand-out assertive moments, but eventually you start to run out of examples. As you struggle to think of assertive times in your life, you start to underrate your assertiveness. On the other hand, if you only have to think of a handful of assertive moments, and your brain pulls those moments from memory easily, then the experience of easily identifying moments of assertiveness gives you more confidence with rating yourself as assertive.
What I find fascinating with the study Kahneman presents is that the brain doesn’t rely on facts or statistics to make judgments and assessments about the world. It is not setting a bar before analysis at which it can say, more examples of this and I am assertive, or fewer examples and I am not assertive. It is operating on feeling and intuition, fluidly moving through the world making judgments by heuristics. The brain is not an objective observer of the world, and its opinions, perspectives, and conclusions are biased by the way it operates. The study suggests that we cannot trust our simple judgments, even when they are about something as personal as our own level of assertiveness.