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If we read a research paper about a study, we may believe the assertions made in that paper even if the research project it references only had a few dozen test subjects.
This is an example of what’s called “extension neglect”: a bias that causes us to ignore the relevant sample size when assessing the validity of a finding, even when that sample size is vital to the assertions being made.
This particular bias is thought to be an offshoot of what’s sometimes called “judgement by prototype,” or “exemplar theory,” both of which say that we tend to categorize the world using archetypes: we have a cognitive model for what a lawyer is, what a rock looks like, and how a car works.
None of these models are applicable in every case, and they will almost always fail to perfectly describe any specific instance of what they reference: they average and reduce in order to create a fundamental, simplified working model of what a thing is.
This applies not just to individual things, but also to concepts—like, for instance, a study that we heuristically simplify so it fits on the same mental shelf as all the other studies we’ve ever read, even if it lacks the scientific heft other studies on that mental shelf possess.
“Duration neglect” is similar in some ways to extension neglect, in that it’s a common bias that causes us to overlook something because of the way our brains tend to simplify and store experiential data.
In this case, our brains lean toward remembering some aspects of an experience at the expense of others, and the duration of an incident is less often stored than other elements, like the order in which it happened within a larger sequence of events.
Thus, it’s possible to be shown a series of pleasant or unpleasant film clips and to remember them as being of a similar duration, even when that was not the case.
These two biases often blend into a somewhat broader heuristic called the “peak—end rule.”
The peak—end rule says, in essence, that we tend to remember and judge experiences primarily based on how we perceived them during their peak and final moments.
It’s possible, then, for us to have a drawn-out, unpleasant experience, but to recall that experience as having been less unpleasant because, at its peak, it wasn’t dramatically worse than the rest of the experience, and because it was less-bad near the end than it was on average.
This heuristic may be the result of our dismissal of time as a core consideration when we form memories, and our tendency to utilize archetypes so that only the barest shape of something is firmly planted in our recollections.
It may be the consequence of our tendency to focus on especially emotionally engaging experiences, which often help determine which portions of a larger experience are the most heightened and form the peak.
It may also result from our cognitive favoritism for the most recent element of an experience. This is sometimes called “recency bias” and is associated with the “availability heuristic,” which says that we tend to recall and make decisions based on memories that are the easiest to bring to mind, and which are therefore often the most recent portions of a particular experience.
Like all biases and heuristics, this jumble of cognitive concepts vary wildly from person to person, in terms of how common they are as strategies and in terms of their potency.
That said, they do seem to be common and useful enough—or at least appealing enough as potentially useful concepts—that they’re utilized across industries where customer and client engagement is key.
The peak—end rule implies that even painful experiences, like surgeries or tumultuous negotiations, can be tempered and rebalanced in the memories of those involved as long as the patient’s final moments at the hospital, or the client’s exit from the office building, are pleasant, peak or peak-adjacent experiences.
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