Tag Archives: Brain teaser

Beware the Brain Melter…

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meninhats

I’m a huge fan of brain teasers. I love pitting my mind and mental quickness against word puzzles and other challenges, so brain teasers are perfect.

A terrific example of a quality brain teaser appeared here a while back: the Men in Hats problem (pictured above).

It’s a great brain teaser because it’s deceptively simple, but requires careful, outside-the-box thinking to figure out how to solve the puzzle.

But there’s another kind of brain teaser out there that’s not intended to be solved. These are more tricks or bits of wordy gamesmanship than brain teasers. I like to think of them as brain melters.

Here’s an example of a brain melter I tweeted a month or two ago:

True or false? Thare are five mistukes im this centence.

Now, parsing it out, you can see the misspelled “thare” (1), the misspelled “mistukes” (2), the misspelled “im” (3), and the misspelled “centence” (4).

But the statement says there are five mistakes when there are only four, which would make the statement false. If you count “five” as a mistake, then it becomes five mistakes, which makes the statement true. But if five mistakes is true, then saying “five” ISN’T a mistake, so the total goes back to four mistakes, and…

You see? You soon find yourself in a brain-melting loop that never goes anywhere. It’s like the barber who shaves only the townsmen who don’t shave themselves. So does he shave himself? If he does, he doesn’t. If he doesn’t, he does.

Still with me?

Okay, here’s another brain melter. (The one, in fact, that inspired this blog post.)

If you choose an answer to this question at random, what is the chance you will be correct?

A) 25%
B) 50%
C) 60%
D) 25%

At first glance, this seems simple. There are four options, so the chances of being correct should be 1 in 4, or 25%.

But wait. Two of the answers are “25%”, meaning that A AND D could lead to the right answer, so those odds become “50%”.

But “50%” as an answer only appears once, so the chances of choosing “50%” are only 25%.

And if you keep following that chain of thought, you circle around and around and around, going from 50% to 25% and back again while your brain dribbles out your ears and down into your shoes.

Beware the brain melters masquerading as brain teasers, my friends.

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Teasing your brain (and your job applicants)

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Did you ever have a job interview where someone posed a mental test or brain teaser?

These were all the rage a few years ago and I’ve heard plenty of stories from friends and acquaintances who applied for jobs only to find themselves wandering down tangential rabbit holes instead of presenting their credentials in the best light.

How many golf balls can fit in a school bus? How much should you charge to wash all the windows in Seattle? Why are manhole covers round? How many piano tuners are there in the entire world?

Google (among other companies) became notorious for this sort of on-the-spot cognitive analysis, but in an interview with The New York Times, senior vice president of people operations at Google Laszlo Bock admitted that these kinds of questions proved completely worthless as predictors of employee creativity or performance.

As a puzzle guy, I can appreciate the spirit behind asking these questions. When you present a seemingly unsolvable puzzle, you’re not really looking for the solution, you’re looking for the resourcefulness of the solver. When you present a brain teaser that demands great results with only two tries, you’re examining the interview’s insightfulness and efficiency.

The problem is… abstract problem-solving isn’t the same as actual problem-solving. I daresay the interview is the most stressful part of many jobs, so the pressure you endure sitting in the hot seat and trying to earn a job overshadows the pressure you’ll endure actually doing that job. After all, there’s not a yes-or-no implied after each question when you’ve got the job, but that uncertainty permeates the interview process.

But, Bock also explains how properly-framed questions about problem-solving can be more useful indicators:

Behavioral interviewing also works — where you’re not giving someone a hypothetical, but you’re starting with a question like, “Give me an example of a time when you solved an analytically difficult problem.” The interesting thing about the behavioral interview is that when you ask somebody to speak to their own experience, and you drill into that, you get two kinds of information. One is you get to see how they actually interacted in a real-world situation, and the valuable “meta” information you get about the candidate is a sense of what they consider to be difficult.

I’ve never had to answer a brain teaser like the ones listed above, not even when I interviewed to be a puzzle guy. Of course, if you ask me how many golf balls can fit in a school bus, my first answer would probably be “more than I could ever need.” Plus I don’t do windows.

[Check out this io9 article for greater detail, including source links and list of former Google interview questions.]

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