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Lessons from Sherlock Holmes: Breadth of Knowledge Is Essential

Once upon a time, Sherlock Holmes urged us to maintain a crisp and clean brain attic: out with the useless junk; in with meticulously organized boxes that are uncluttered by useless paraphernalia.

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


Once upon a time, Sherlock Holmes urged us to maintain a crisp and clean brain attic: out with the useless junk; in with meticulously organized boxes that are uncluttered by useless paraphernalia. But how exactly do you determine what should be in, and what, out? As it turns out, Holmes’s definition of relevance is actually far wider than it would appear to be at first glance – and than would be comfortable for someone looking to get away with as sparse an attic as possible and still be successful.

In “The Valley of Fear,” Inspector MacDonald is flummoxed when Holmes suggests that he abandon the case altogether. But from bewilderment, his mood quickly escalates to anger, when the detective appears to veer entirely off topic in discussing his reading of an old book on the history of Manor House (“You are making fools of us, Mr. Holmes!” Mac cries). Unperturbed, Holmes presses on:

“…you will admit that there are various associations of interest connected with this ancient house.”

“I don’t doubt it, Mr. Holmes; but that is no business of ours.”

“Is it not? Is it not? Breadth of view, my dear Mr. Mac, is one of the essentials of our profession. The interplay of ideas and the oblique uses of knowledge are often of extraordinary interest. You will excuse these remarks from one who, though a mere connoisseur of crime, is still rather older and perhaps more experienced than yourself.”

“I’m the first to admit that,” said the detective heartily. “You get to your point, I admit; but you have such a deuced round-the-corner way of doing it.”


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Here, Holmes adds an important caveat to his theory of the useful mind attic: the most surprising of articles can end up being useful in the most surprising of ways. Often, the idea that will, in Holmes’s case, solve the mystery–and in the case of someone like me, may just help resolve whatever nagging problem has been swimming around in my head–comes from a place you would have never predicted beforehand.

The value of an open mind

This notion resembles the Holmesian insight on the importance of imagination that I wrote about earlier, but it is not exactly the same thing. While the former focuses on creative insight gained by looking at a problem from a new angle or in a different frame, the current approach examines the importance of opening your mind to new inputs, however unrelated they may seem.

It is easy, when faced with a problem, to tackle it in the most logical and straightforward way possible. In this case, Mac follows the lead of the bicycle: a bicycle is found in the bushes of the house where a crime has taken place. Right away, the inspector decides that it is the only tangible lead and proceeds to spend an inordinate amount of energy tracking the bicycle’s owner, ignoring other possible ways to approach the investigation. Of course, he gets exactly nowhere; a bicyclist wearing a yellow coat is spotted in just about every region, from Leicester to Liverpool, and there appears to be little hope of pinning down the right suspect.

True, Inspector MacDonald is not doing anything particularly wrong. If he keeps at it, he might well find the man he thinks he is looking for. But in this direct, hitting-the-problem-over-the-head approach, he is apt to plod along without necessarily gaining as much as the energy expenditure would suggest he should. Sometimes, the analytical way is not the best or the quickest. And in those instances, it may well be better to go off the beaten path and search for–or be receptive to–other signs, even when they are as seemingly unrelated in the extreme as the Civil War and events of 1644 to a present-day mystery.

Consider this study of problem-solving (pdf), which used a classic paradigm (known as compound remote associates) that allows someone to solve a problem either the Inspector Mac way, by plodding along step by incremental step, or the Holmes way, by searching for other elements that might lead to a faster and more effective solution. The end result may be the same; the approach and time spent getting there couldn’t be more different.

In the paradigm, participants are presented with three words, such as crab, pine, and sauce. They are then asked to think of a single word that can be added to each of the prompts to form a compound or a two-word phrase. Now, there are two ways to solve this problem. One comes from insight, or seeing the right word after a few seconds of searching, and the other comes from an analytical approach, or trying out word after word until one fits. Here, the proper answer is apple (crabapple, pineapple, applesauce), and one can arrive at it either by seeing the solution, or by going through a list of possible candidates (Cake? Works for crab but not pine. Grass? Ditto. Etc.).

This particular experiment is notable in that it goes a step beyond seeing who comes up with which approach, or who is a Holmes and who, a Mac. It also looks at the neural correlates of participants’ brains as they search for a solution. In other words, does the actual brain activity of a Holmes differ from that of a Mac?

What the researchers found was that in the brain, insight and analysis look quite different. About 300 milliseconds before the insightful solution, there was a burst of high-frequency activity in the anterior temporal lobe, which corresponded to activity in the brain region known as the right anterior superior-temporal gyrus, an area that has been implicated in bringing together and integrating otherwise unconnected thoughts. What was going on?

Given the exact pattern of activity, as measured by both EEG and fMRI, it appeared that the brains of the Holmeses were sensitive to the presence of a however weak potential solution and worked to reduce other interfering inputs to facilitate its retrieval. Meanwhile, the brains of the Macs weren’t even aware that there was something there to retrieve.

What’s more, in a follow-up study, the researchers found that even the resting state brain–that is, the brain before it has even seen the problem–was different for someone who was about to use insight versus someone who was about to approach the problem analytically. In the first case, there was increased activity in the temporal lobes of both the right and left hemispheres of the brain, suggesting that the areas that process lexical and semantic information were being primed, and over midfrontal cortex, suggesting that the anterior cingulate (where the activity originated) was helping detect weak, subconscious solutions and pay attention to them once they were detected. In the second case, there was increased activity in the posterior, or visual, cortex, suggesting that attention was being directed outward. So, even at the start, brains were preparing differently; they had, it seems, trained themselves in two distinct ways of approaching a possible problem (an interesting side note: the researchers, in a further study, also found differences in brain resting-state activity, suggesting that there is a fundamental processing difference that is always present – but how it gets that way remains unclear).

How does one become a Holmes, not a Mac?

The problem, of course, is how to know when you’ve stumbled upon something potentially useful. How does your brain know that there is a possible solution out there? How did that possible solution even get there to begin with?

And that is where your general mindset comes in: is there a standing openness to inputs no matter how strange or unnecessary they might seem, as opposed to a tendency to dismiss anything that is potentially distracting? Is that open-minded stance your habitual approach, the way that you train yourself to think and to look at the world? As Louis Pasteur once said, “Chance favors only the prepared mind,” – and that mind is one which is open to the chance in the first place.

Indeed, with practice, one might become better at sensing what may and may not prove useful, what to store away for future reference and what to throw out for the time being. Something that at first glance might seem like simple intuition is actually far more–a knowledge that is actually based on countless hours of practice, of training yourself to be open, to integrate experiences in your mind until you become familiar with the patterns and directions those experiences tend to take. Then, you are far less likely to spend days traipsing in mud through the countryside in pursuit of a cyclist you may or may not have a chance of finding. Instead, you may just pick up the history book that is so gallantly being offered for your use.

Photo credit: By Arthur Ignatius Keller 1866-1924 (Rtrace was original uploder at EN.Wikipedia) (EN.Wikipedia) [Public domain], via Wikimedia Commons

Previously in this series:

Don’t Just See, Observe: What Sherlock Holmes Can Teach Us About Mindful Decisions Lessons from Sherlock Holmes: Paying Attention to What Isn’t There Lessons from Sherlock Holmes: Cultivate What You Know to Optimize How You Decide Lessons from Sherlock Holmes: Perspective Is Everything, Details Alone Are Nothing Lessons from Sherlock Holmes: Don’t Underestimate the Importance of Imagination Lessons from Sherlock Holmes: Confidence Is good; Overconfidence, Not So Much Lessons from Sherlock Holmes: The Situation Is in the Mindset of the Observer Lessons from Sherlock Holmes: The Power of Public Opinion Lessons from Sherlock Holmes: Don’t Tangle Two Lines of Thought

Maria Konnikova is a science journalist and professional poker player. She is author of the best-selling books The Biggest Bluff (Penguin Press, 2020), The Confidence Game (Viking Press, 2016) and Mastermind: How to Think Like Sherlock Holmes (Viking Press, 2013).

More by Maria Konnikova