I’ve been a fan of Sherlock Holmes since I was a teenager. I’ve always admired the great detective’s ability to solve crimes with a combination of keen observation, deductive reasoning and imagination. I also envied his ability to discern someone’s occupation, family background, or where they’ve been recently just by looking at them.

I was hoping that Mastermind: How to Think Like Sherlock Holmes by Maria Konnikova would teach me some of these things.

Maria Konnikova is a best-selling author, journalist and a professional poker player. She holds a PhD in Psychology from Columbia University.

Mastermind: How to Think Like Sherlock Holmes
By Maria Konnikova
Penguin Books, New York, 2013

Mastermind is organized around the steps in Sherlock Holmes’ method of detection, which is basically the scientific method:

1. Define: Clearly identify the problem you’re trying to solve or the question you’re trying to answer. This sets the context for the remaining steps.  
2. Observe: Gather facts. Only facts. Resist the urge to rush to judgement or jump to conclusions.
3. Hypothesize: Imagine possible answers or explanations that fit the facts you’ve observed. At the start, there will likely be more than one.
4. Test and deduce: Test your hypotheses by conducting experiments or asking questions that help you gather more information. Eliminate any options that are impossible.
5. Refine: Update your hypotheses based on new information and repeat these steps until only one remains.

As Holmes himself says on many occasions, “when you have eliminated the impossible, whatever remains, however improbable, must be the truth.”

Thinking, Watson and Holmes

What makes this process so difficult, Konnikova explains, is that we’re hard wired to make snap judgements. She draws heavily on the work of Nobel Laureate Daniel Kahneman who’s book Thinking, Fast and Slow popularized the idea that our brains have two distinct systems of thinking.

The first, which Kahneman called System 1, is fast, intuitive and reactive. It’s the part of our brain that’s highly evolved to detect predators, intruders and other threats. It’s critical to our survival.

System 2, on the other hand, is slow, methodical and deliberate. This is the part of our brain we use to solve problems, overcome obstacles, and make plans for the future. 

In a clever narrative move, Konnikova renames them System Watson and System Holmes.

Most of the time, most of us operate under System Watson.

To successfully follow Holmes’ methods, we must train our minds to slow down, step back and operate under System Holmes.  

Thinking Mindfully

Whether you want to solve crimes or identify the occupation of random strangers at a party, Maria Konnikova says the key is mindfulness. You need to be present, attentive, and consciously engaged. 

Mastermind devotes a chapter to each of the steps in Holmes method. In every one of them, Konnikova urges a mindful approach.

For example, in the chapter on observation, Konnikova recommends that we observe in a focused and deliberate way. She suggests that we:

• Be selective in what we observe: have a goal or a question in mind and observe things that help us achieve it or answer it.
• Be objective: don’t let biases and pre-conceptions lead us to make fast judgements. In other words, first observe, then deduce.
• Write down or repeat out loud (as Holmes often does to Watson) our observations. This helps us spot judgements that are not actually observations. It also helps to highlight gaps, contradictions or impossibilities that can suggest experiments or further lines of inquiry.
• Be inclusive: use all our senses, not just sight. We should note the absence of sensory evidence too. The “curious incident” of the dog in the night from The Adventure of Silver Blaze is a famous example:

Inspector Gregson: Is there any other point to which you would wish to draw my attention?
Sherlock Holmes: To the curious incident of the dog in the night-time.
Gregson: The dog did nothing in the night-time.
Holmes: That was the curious incident.

All these suggestions are designed to force mindfulness, to override System Watson and to engage System Holmes.

In the chapter on imagination and creativity, Konnikova illustrates how Holmes arranges and recombines observations into new or alternative possibilities that can then be used for further investigation. This is the process of hypothesizing, and she says we should begin from a place of open-minded possibility.

Yet here too, we must be mindful because we are constrained by the facts. Whatever ideas we come up with must fit the observed facts.

Konnikova doesn’t claim that learning Holmes’ way of thinking is easy, but she does say it’s possible if we adopt Carol Dweck’s idea of a growth mindset. We can grow and learn new skills. The most important one is mindfulness.

“…the most powerful mind is the quiet mind. It is the mind that is present, reflective, mindful of its thoughts and its state.” [p. 257]

Unsolicited Feedback

Mastermind did provide some helpful guidance about how to think like the mastermind himself, but extracting the details was hard work. 

In each chapter, Konnikova illustrates her ideas with lengthy retellings of incidents from one or more of Sherlock Holmes’ cases. While I love to revisit these stories as much as any Holmes fan, I found this got tedious. She also dives deeply into research on brain science and cognitive biases, most of which I’ve read in other books. 

There was so much of this material that I found it difficult and frustrating at times to distill the key points and methods.

That said, reading Mastermind has motivated me to adopt Holmes’ methods, to be more analytical and especially more mindful in how I think and observe. 

I decided to try out these methods on a recent Friday afternoon flight from San Francisco to Seattle while returning home from a business trip.

What could I deduce about the person sitting next to me?  

I noticed she boarded the plane carrying only a large backpack and a brightly colored paper gift bag. Later in the flight I saw that the bag contained some dried flowers: lavender, I think. She declined the pretzels offered by the flight attendant and instead fished out of her backpack a Ziploc bag filled with apple slices just starting to turn brown.

I gleaned all this from a few sideways glances, which is about all I could politely manage on a packed flight in economy.  

From the apple slices I hypothesized that she lived in the San Francisco area and had prepared herself a snack a few hours before the flight. This also suggested that she flew regularly and knew to bring her own food if she wanted something healthy. 

The absence of any carry-on luggage other than a backpack made me think she was making a quick trip, maybe just for the weekend. And from the gift bag of dried lavender I speculated she might be visiting a relative, possibly her mother. 

Now I could be wrong on any or all of these hypotheses. She could have checked her luggage and been making a much longer trip. She might have been staying with a friend in San Francisco who gave her the apple slices for the trip home. And the lavender could have been a gift she received rather than one she was giving away. I didn’t get the chance to test any of these ideas. It would have been creepy to ask.

But it was fun way to pass the time on a boring flight.

Thanks for reading.

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Thanks again to Molly @ Silver Button Books for recommending this one.