This is just a short announcement the ebook is now on Amazon in the Kindle store:

Buy at Amazon: http://www.amazon.com/dp/B007ONNCWO

(It’s worth mentioning you can still read the ebook without a Kindle. I personally have downloaded the Kindle apps for both my PC and tablet and they work great.)

And if you like the puzzles on this blog, I have a small favor to ask: please, please add a customer review on Amazon. I really need a couple of reviews to help establish the book’s quality. I’m hoping a few of you can speak up to the high quality of puzzles on this site (even a short sentence like “A great collection of puzzles for the anyone that likes math” would be tremendously helpful.) Thanks.

It’s plainly titled Math Puzzles: classic riddles in counting, geometry, probability, and game theory.

Buy at Gumroad: https://gumroad.com/l/pjHS

The ebook costs $4.99 and it contains 70 of the best puzzles from the Monday puzzle series. The link above will take you to a website Gumroad where you can pay for the book by credit card. You’ll immediately get a link to download the ebook, and you will also get a copy by email just in case.

This is the first time I’m selling an ebook, so if there are any hitches, please email me immediately (presh@mindyourdecisions.com) and I’ll be happy to solve the problem.

Very important: I should mention the ebook does not contain any new puzzles, so don’t buy it if you’re expecting new puzzles.

That said, the ebook is nice way to read these puzzles, and it would make a perfect gift for anyone who loves math.

Want a free copy?

If you run a reasonably sized blog, I’d be happy to send you a free copy. I would ask you post a review on your blog with your honest opinion. I’m also happy to do interviews over email.

Email me if you’re interested: presh@mindyourdecisions.com

Coming soon: Kindle and other versions

Personally I prefer ebooks in pdf format with no DRM. I am guessing you guys would feel the same way, so that’s why I decided to go with direct distribution.

That said, many people prefer to buy things from Amazon and other marketplaces, so soon the ebook will be available for the Kindle and other ebook readers too.

Thanks for all your support!

This part is going to sound sappy, but it’s something I really want to say.

I’ve been writing this blog for nearly 5 years now, and I have to thank you all for all you’ve done. The feedback through email, comments, and shared posts has been amazing and has kept me motivated to keep writing more.

This ebook would never have been possible without all of that support.

But today I am thrilled to say there is finally a great game theory introduction that I can recommend. The e-book is called:

Game Theory 101: The Basics & Extensive Form

The book covers the basics of game theory, including the Prisoner’s Dilemma, mixed strategy equilibrium, and it also covers extensive form games (game trees) in which players move in sequence, like the ultimatum game. There are tons of diagrams and lengthy discussions to help you understand the concepts.

One of the remarkable things is how cheap the book is. This ebook which has over 100 pages is selling for a mere $2.99 on Amazon (there is also a lite version for $0.99 called Game Theory 101: The Basics, but I would suggest the $2.99 version as it is more comprehensive and suited for readers of this site).

Very important: while the book says it’s available for Kindle, you don’t need a Kindle to read it. You can read the book on your PC, Mac, iPhone, Android phone, or virtually any device by downloading an appropriate Kindle reading app.

About the author William Spaniel

The book is written by William Spaniel, a name that may be familiar to some of you. William Spaniel has created an impressive series of Youtube videos with the same brand name of “Game Theory 101.” He has also been a long time reader of this blog, and he has contributed with many comments and a great idea for how to find cheap gas using game theory (a bit more on that in the interview below).

I really respect William for writing the book and creating the videos, and even more so, it’s impressive he is doing this while he’s a student pursuing a PhD in political science at the University of Rochester. I got a chance to interview William Spaniel and I picked his brain about why he wrote the book and created the videos. I also got his opinion about why game theory textbooks are often not very good.

I hope you enjoy the interview, and definitely be sure to check out the ebook Game Theory 101.

What got you interested in game theory?

WILLIAM SPANIEL: A paper called Ethnic War as a Commitment Problem. Most people think I am an economist, but I am actually a political scientist by trade. Unlike economics, political science does not have any core tenants that all undergrads at every department must know before they can graduate. I think this leads to a watered-down field with mostly murky theories. But the concept of a commitment problem was refreshingly clear. I figured if game theory could create such focus in the otherwise directionless world of political science, I should learn more about it.

What motivated you to make Youtube videos?

I had played around with YouTube a bit prior to the creation of Game Theory 101. I noticed there were no good comparable options out there. When I started creating lesson plans to teach my roommate the field, I figured I would throw a few short clips on YouTube. It took off past my wildest expectations. Two years later, I have almost 100 videos, a partnership with YouTube, a website (gametheory101.com), and a book series.

Why did you decide to write a book?

My friend Chris pestered me endlessly until I wrote the book. This is the same friend from the car ride where we used the secretary problem to find cheap gas.

I get a lot of emails and comments with strange requests from this blog. What’s an odd/funny request you’ve gotten?

Every December and May/June, I get a few desperate emails from students offering hundreds of dollars to complete their take-home finals for them. I am still unsure how to tell them “no.”

Most game theory textbooks I have read are not very good. Why is that?

There are two reasons. First, every other game theory textbook I have read is written as a reference manual, not a teaching book. Every serious game theorist needs one of these on their bookshelf, but they are completely inaccessible if you do not already understand most of what they discuss. I do not understand why everyone writes this way. Maybe publishers will not publish anything less rigorous. Perhaps professors simply write in the way they were taught. Regardless, that is just how the genre is.

Second, print textbooks have restraints that digital textbooks do not have to worry about. When you take any sort of math class, the first thing that a professor stresses is that math is best learned through repetition. Yet textbooks often show a single example to introduce a new concept! How are you supposed to learn through repetition when you see one example and have 30 practice problems to contend with? But more examples require more paper and ink to publish, which publishers will not allow.

The digital market has no comparable restrictions—megabyte transfers are dirt cheap in comparison to traditional printing and shipping. Thus, I can cram multiple examples of every concept, show picture-by-picture how to best look at a game, and calculate all solutions line-by-line. A traditional publisher would have a heart attack if he saw such a manuscript, yet I can get away with selling a book less than a dollar.

You have a basic book for $0.99 and another one for $2.99. What’s the difference?

The Game Theory 101 textbook is an ongoing project. My $0.99 book is what you might think of as the first chapter. It covers how to solve basic matrix or strategic form games, like the prisoner’s dilemma, matching pennies, and chicken. The $2.99 book is the first two chapters. It includes everything in the first book, plus extensive form games. I recommend anyone who is taking an actual game theory class or who wants a deeper understanding of the field to buy the larger book. If you only have a casual interest in game theory or just have a micro economics test with a splash of game theory, the first one is the best bet.

Why split the book at all? One of the neat things about digital publishing is that you can sell exactly what the consumer needs. The average microeconomics or game theory class covers just a fraction of the material in a normal game theory textbook. Why should you spend money for the part of the book that you will never use?

I am in the process if writing two more chapters. When I finish them, I will package them in a similar way. I understand that it might be a little daunting for the consumer to see so many options, but I think the money they will save makes it worthwhile.

Thanks for the interview. Be sure to check out Game Theory 101: The Basics & Extensive Form, it’s a great read, and stay tuned as William Spaniel releases more chapters.

I say this jokingly, but it is pretty much true. There is Amazon for consumer products, Yelp for restaurants and site-seeing, TripAdvisor for hotels, and Angie’s List for repair services. Even at the end of the day when I want a beer, there’s BeerAdvocate.

Review websites are a tremendous service and they have helped me make a lot more informed decisions.

Fake reviews spoil the game

The downside is review websites are victims of their own success. There is a huge market for fake positive reviews, ranging from owners that self-promote their business, patrons that are bribed with discounts for good reviews, and professional liars that sell positive reviews for $1 a piece.

Fake reviewers make me extremely mad, and they deserve punishment for the tremendous injustice they are doing to society. But there’s no point in getting angry as retribution is an unrealistic goal.

The best thing to do is to ignore these fake reviews. If fake reviews can be identified, then there will be less of a market for them.

Today I came across a useful and free tool in the battle. This is a computer algorithm that can spot spammers much more accurately than we can. In the study, the algorithm was nearly 90 percent accurate versus humans just about 60 percent. More about this after the jump.

Also a small administrative note: this website is undergoing account maintenance and may be offline from October 29th, from 12:00am to 4:00am EDT.

H/T: New York Times via The Responsibility Project

The Review Sniper

The algorithm is called the Review Sniper and there is a demo version available for free at the website ReviewSniper.org

The way it works is simple: you paste in a review, and click “submit.” The Review Sniper then tells you whether the review falls into the 4 categories of “truthful, mostly truthful, somewhat deceptive, or deceptive.”

The directions are all self-explanatory at the website:

Currently the tool is completely free and it works best for hotel reviews because those are the reviews it was tested with.

The theory of fake reviews

The Review Sniper is the result of work from researchers at Cornell. In a recent paper, the researchers worked out an algorithm that could identify deceptive opinion spam, which are “fictitious opinions that have been deliberately written to sound authentic, in order to deceive the reader.”

The algorithm relies on a set of linguistic clues and word analyses to parse out genuine reviews from deceptive ones. The analysis is way over my head, so I will not conjecture any more. But you can read about the details in the following paper.

To test the accuracy of the algorithm, the researchers compiled a set of reviews. They employed freelance writers to produce 400 deceptive reviews about Chicago hotels. These got combined with 400 reviews mined from TripAdvisor that seemed to be genuine (they were from repeat users, not overly positive, and long).

Three volunteers were asked to judge the reviews as fake or genuine, and the results were compared side by side with the algorithm. On the whole, the volunteers were only about 60 percent accurate in their conclusions. By contract, the algorithm was nearly 90 percent accurate in its identification.

That people are credulous is no surprise, and that is it helps to have emotionless algorithms to parse out fake reviews.

A closing test

The research so far seems limited to hotel reviews, but one hopes further research will make deceptive reviews a thing of the past.

If you want to test your own skill, see if you can identify whether the following reviews are truthful or deceptive.

Here are the reviews, used as examples in the paper.

The first review:

I have stayed at many hotels traveling for both business and pleasure and I can honestly stay that The James is tops. The service at the hotel is first class. The rooms are modern and very comfortable. The location is perfect within walking distance to all of the great sights and restaurants. Highly recommend to both business travellers and couples.

And the second review:

My husband and I stayed at the James Chicago Hotel for our anniversary. This place is fantastic! We knew as soon as we arrived we made the right choice! The rooms are BEAUTIFUL and the staff very attentive and wonderful!! The area of the hotel is great, since I love to shop I couldn’t ask for more!! We will definatly be back to Chicago and we will for sure be back to the James Chicago.

Do you have your answers? I can report that my guesses were right.

The answer is “Gur svefg bar vf zbfgyl gehgushy naq gur frpbaq vf qrprcgvir” (paste into rot13 to decode)

So the next time you come across a product with a suspicious review, you might want to check it out with the current demo version of Review Sniper.

An introductory story

Before I get to the book review, I want to tell a short story.

My friend’s office had a problem. There were many times that clients would call, and no one would pick up the phone. The boss yelled at everyone for being irresponsible. But were the employees really lazy, or was there something else going on?

I suggested the employees were not to blame when I wrote about this problem four years ago. The phone answering system, it turned out, was really poorly designed. Calls first went to the office secretary, but if she was out, then the call would roll over to ALL phones in the office. The situation created a game of chicken where each employee held off, hoping someone else would answer the call. And so many times no one answered the phones.

It was not the case that employees were lazy. They were simply trying to avoid extra work and hope someone else would cover. The problem could be solved easily by assigning shifts to answer phone calls on backup, restoring individual responsibility.

The lesson of that story was that context matters a lot. If you create a situation that encourages free riders, you are bound to end up with poor results. And by analogy, if you alter rules to encourage cooperation, you can end up with amazing results.

Situations Matter: a book about how context affects our world

Understanding the power of context is crucial to making good decisions. And on that note, I highly suggest the book Situations Matter by Sam Sommers, a psychology professor at Tufts University.

I was fortunate to receive an advance copy for review thanks to TLC Book Tours.

The book will be released on December 29, so keep an eye out for it, or get updates through Sam Sommer’s:

–Twitter
–Facebook page
–Website.

As a whole, Situations Matter was a fun and light read, with a discussion of many famous and interesting psychological experiments mixed in with a handful of anecdotes from the author’s life and pop culture references like Seinfeld.

I read the book in a couple of weeks, and it has definitely kept me thinking about ways I can improve my decisions by thinking about context. Here are 3 of the things I enjoyed about the book prefaced by one caveat.

A small caveat

A lot of the book talks about how people can be influenced and/or manipulated by context. There is an entire chapter about conformity that discusses the famous Milgram obedience and the Asch conformity experiments.

I agree that conformity is a powerful force, and there is a strong tendency for people to go with the flow.

But personally I have a long history of being eccentric and not caring what people think. And of course, this site is all about minding your own decisions and not others.

So the small warning is that you may find some of the advice is things you already practice: like it’s fine to disagree with groups of friends, and it’s okay to stand out in a crowd.

3 reasons I enjoyed this book

1. The book is conversational

I used to think non-fiction books were all about their subject matter. Now I find that I care a lot more about how a book is written and whether I will enjoy reading it.

Sommers does a great job of keeping the book fun. This is not always an easy task when you are dealing with experiments and trying to explain psychological concepts.

But Sommers manages to keep the book fun through personal stories and by writing in a conversational tone, frequently addressing “you” the reader. For instance, the book opens with a story about Sommers missing a flight, and he vents out his frustrations to bring you into his shoes. He then uses the situation as an opportunity to apply his knowledge to successfully negotiate a hotel and meal voucher.

I felt the casual tone helped out, and while that does mean the text is chatty and not always succinct, it was a writing style that I enjoyed overall.

2. The chapter on love is great

I’ve been to a lot of weddings recently, and it is the same story over and over again. People always talk about the same romanticized version of true love and how the young couple before you exemplifies this concept.

What is never talked about, because it is a mundane detail, is that love and relationships are dependent on more than good looks and compatible personalities. Relationships depend a lot on circumstances, like where people lived, the friends they knew, and where they met (research shows that people exercising, for instance, are more primed for arousal).

The chapter goes into research about how context can influence people’s feelings of attraction. I don’t want to spoil any of the interesting experiments that are mentioned, but if you must know, Sommers does talk about this experiment (his explanation is better)

Even if you do not typically read books about psychology, I would definitely recommend reading the chapter on love.

3. The book got me thinking about context

The biggest compliment I can give is to say the book has gotten me to think about context more.

When we go about our routine, we can overlook other people’s routines and the situations they face. In a concluding example in the book, Sommers talks about how he was trying to find a spot in a busy parking lot. One driver appeared to be getting out, but then sat there stopped.

Initially Sommers was angry because waiting was making him late (I mean who sits there in a spot?). But then he realized he should consider the other person’s situation and stay calm. It turned out later the driver was having auto problems, and was not stopped out of spite or indifference.

I am using the lessons in the book to think a bit more closely in my actions. The other day I was sending an email related to career networking. I did all the usual edits, but then I thought about the other side.

Would the person be more likely to respond if they got the email in the morning or evening? Was there a way they could answer me quickly, or did I overwhelm them with a long email? These questions made me shorten the email, and I sent it out during lunchtime rather than in the morning when I expected her to be backed up with email.

The book did a good job to get me thinking about context, and I am sure it will get you thinking about a few things too.

Find this book when it comes out

As I mentioned before, Situations Matter will be released on December 29. Definitely keep an eye on it, or pre-order it now (links to stores on this page).

Here are some places you can connect with Sam Sommers and get updates on the book.

–Twitter for Sam Sommers

–Facebook page for Sommers

–Situations Matter: book website.