When asked the other day about a bakery near my home, I responded that I’d recently eaten its mouth-watering chocolate chip cookies. My wife corrected me, noting that the cookies I ate were actually oatmeal raisin.
Why did I make this memory error? Is this an early sign of impending dementia? Should I call my doctor?
Or is forgetting the details of a dessert a good thing, given that everyday life is filled with an enormous number of details, too many for a finite human brain to remember accurately?
I am a cognitive scientist and have been studying human perception and cognition for more than 30 years. My colleagues and I have been developing new theoretical and experimental ways to explore this kind of error. Are these memory mistakes a bad thing, resulting from faulty mental processing? Or, counterintuitively, could they be a good thing, a desirable side effect of a cognitive system with limited capacity working efficiently? We’re leaning toward the latter – that memory errors may actually indicate a way in which the human cognitive system is “optimal” or “rational.”
Are people rational?
For decades, cognitive scientists have thought about whether human cognition is strictly rational. Starting in the 1960s, psychologists Daniel Kahneman and Amos Tversky conducted pioneering research on this topic. They concluded that people often use “quick and dirty” mental strategies, also known as heuristics.
For example, when asked whether the English language has more words starting with the letter “k” or with “k” as the third letter, most people say there are more words starting with “k.” Kahneman and Tversky argued that people reach this conclusion by quickly thinking of words that start with “k” and with “k” in the third position, and noticing that they can think of more words with that initial “k.” Kahneman and Tversky referred to this strategy as the “availability heuristic” – what comes most easily to mind influences your conclusion.
Although heuristics often yield good results, they sometimes do not. Therefore, Kahneman and Tversky argued that, no, human cognition is not optimal. Indeed, the English language has many more words with “k” in the third position than words starting with “k.”
Suboptimal or the best it can be?
In the 1980s, however, research started appearing in the scientific literature suggesting that human perception and cognition might often be optimal. For instance, several studies found that people combine information from multiple senses – such as vision and hearing, or vision and touch – in a manner that is statistically optimal, despite noise in the sensory signals.
How well can you gauge the speed of this ball coming at you?
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Perhaps most important, research showed that at least some instances of seemingly suboptimal behavior are actually the opposite. For example, it was well…