Customer Reviews

The Drunkard's Walk: How Randomness Rules Our Lives

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I just love books like this - especially when they're as well-written as this one. The author, a physicist, proceeds to show the reader how randomness plays a much greater role in everyday life than one might think. As he discusses the basics of probability and statistics, he provides wonderful illustrations from fields as wide-ranging as sports, medicine, psychology, the stock market, etc., etc. He does an excellent job in driving home the fact that the true probability of events is not intuitive. Perhaps because of this anti-intuitiveness, I had to read a few paragraphs more than once to allow the point being made to sink in. One enigma that is particularly well explained is the Monty Hall (Let's Make a Deal) problem. The writing style is clear, accessible, very friendly, quite authoritative, engaging and often very witty. This book can be enjoyed by absolutely everyone, but I suspect that math and science buffs will savor it the most. By the way, the math-phobic need not fear: the book does not contain a single mathematical formula.

We all like to think that we determine our own destiny, that we are the all-mighty purveyors of our success and failure, that through the illusion of control we can gain an understanding of all cause and effect to our existence. How about the success of Bill Gates or Mark Zuckerbergs of the world Surely, they are deserving of the billions of dollars they have earned and the accolades that have been poured down on them. Mr. Mlodinow will argue otherwise. Our successes and failures have more to do with chance and stubborn stick-to-itiveness than anything having to do with cause and effect. When we get a lucky break, that's exactly what it is, a lucky break. The numbers will prove this to be so. Mr. Mlodinow argues that our ability to understand the past is practically perfect but our ability to predict the future using those same cause and effect indicators is very poor. In fact, chance and random numbers would be a better predictor. When the performance of Mutual Fund managers is measure against the performance of random numbers, the result is the same. Individual behavior mirrors that of the drunkard's walk, the path of an individual molecule as it travels through a gas or liquid. We can only predict the probability of a certain behaviour, not its final outcome. Our own path through life involves a series of chance events that have lead us to where we sit at the present moment. To think back and understand that existence as having been determined by individual factors from the past is to suffer from the illusion of control. We like to think we have it. In fact, our very existence can depend upon it but in point of fact, it doesn't exist. The likelihood of publishing that book or getting that next promotion or finding that perfect partner has more to do with chance than anything to do with what we can control so we'd rather pretend than accept.

Excellent book on the history of statistics. Mlodinow does a beautiful of job of going through a basic course in statistics with insightful applications, while looking at the lives of some of the mathematicians and scientists that contributed to the field. Good writing and captivating story-telling.
The last chapter was a tad disappointing, the conclusion was approached from more of a psychological perspective as opposed to the mathematical approach to sociology that I was expecting. If you are interested in some of the psychological biases that the author explores in the last chapter I recommend 'Predictably Irrational' by Dan Ariely as well.

Have you ever flipped a coin 100 times to see the sequence of heads and tails that comes up? If you have, you know that there can be long streaks of heads and tails. Random results that end up 50-50 don't look that way in the short term.

Human perception is such that we like to find patterns where none exist. I remember the CEO of a company I worked for would draw a trend line through one data point with great authority, totally unaware of what he was doing.

More often, we judge by samples of behavior and time that are too short to be representative. Professor Mlodinow does a good job of showing how executives are often fired just before they get their best results, and how seldom the new executive does any better than the prior one.

In sports, we get all excited about streaks. Professor Mlodinow dampens that enthusiasm by pointing out that like streaks can occur randomly. We need to check to see if the streak exceeds the expected degree of variation before deciding that something significant has taken place. (But don't stop cheering on your favorite team and players.)

The book also provides lots of thumbnail sketches of the human side of those who have advanced the science and math behind our ability to measure and understand randomness. In fact, I don't recall a book on this subject with better anecdotes about the scientists and mathematicians. That's the reward in this book if you already know about randomness.

If you know nothing on the subject, this book is the gentlest possible introduction.

Enjoy!

For those of us who trust our instincts, this book will show us the error of our ways. You may wonder whether a book about probability could hold your interest but physicist and author Leonard Mlodinow starts out gently and builds his argument that life is more random than we ever knew. At the same time he offers some reasoning tools that can improve our decision-making.

The Drunkard's Walk: How Randomness Rules Our Lives is structured loosely around a history of probability theory. Some of the biographical material about early thinkers in the field--Cardano, Fermat, Pascal to name a few--is essential to the story of how our modern concepts developed, but more forgettable than the concepts arising from their work. Mlodinow uses a wide variety of examples to illustrate the availability bias, the meaning of the sample space, and the law of large numbers; the latter states that the larger the sample, the more the average converges toward the expected value. The more times you toss a coin, in other words, the closer the number of heads will be to 50% of the tosses. That's one you could assume through intuition, but did you know that it took Jacob Bernoulli 20 years to prove it mathematically? And while the probability of flipping five heads in a row is ... well, not small (this is not a book about math), the odds of the sixth coin toss being a head is still 50%.

Mlodinow makes fairly interesting work of the "Monty question:" if you are on "Let's Make a Deal" and choose door #1 for a grand prize, and before revealing your choice Monty Hall opens door #2 to reveal a goat, then offers you the chance to switch to door #3, should you switch? You may be surprised to know that your odds of the grand prize are better if you DO switch. If you want to know why, read this book. The reader is handled gently as the discussion moves to statistics and the random distribution, or bell curve; and to the "drunkard's walk" of molecules moving through a liquid or gas.

I promise you that it's all more interesting than it sounds, and while I'm not about to take my new insights to the roulette wheel or the Lotto machines, I did spend a happy nine hours listening to the unabridged audio. Given Mlodinow's credentials as Caltech visiting lecturer and coauthor (with Stephen Hawking) of "A Briefer History of Time," I hope it's safe to say that this book simplifies without distorting the subject matter. It certainly entertains without over-taxing the reader's comprehension.

Linda Bulger, 2010

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"I have tried in this book to present the basic concepts of randomness, to illustrate how they apply to human affairs, and to present my views that its effects are largely overlooked in our interpretations of events and in our expectations and decisions. It may come as an epiphany merely to recognize the ubiquitous role of random processes [including chance and uncertainty] in our lives; the true power of the theory of random processes, however, lies in the fact that once we understand the nature of random processes, we can alter the way we perceive the events that happen around us."

The above is found in this revealing, engaging, and readable book by Leonard Mlodinow, PhD (physics) who now teaches about randomness to future scientists at the California Institute of Technology. (He also co-authored with Dr. Stephen Hawking the book "A Briefer History of Time.")

This book's title comes from a mathematical term describing random motion (such as the paths molecules follow as they fly through space, bumping and being bumped by, their sister molecules).

All chapters are meant to lead up to the book' final chapter (that has the same title as the book's title). Generally, the beginning chapters look in a historical context at basic but important concepts in probability theory and statistical inference.

(Probability is a numerical value that measures, estimates, or predicts the degree of uncertainty in which an event will occur. Statistical inference {also called inductive statistics} deals with inferences about a population based on a sample {that is, based on limited data} of that population. Thus, the use of probability theory is important since it allows the sample maker {with only limited data about a certain population} to analyse the risk or uncertainty associated with making a decision about that population.)

Specifically, this book draws from many disciplines, from mathematics and the traditional sciences as well as cognitive psychology, behavioural economics, and modern neuroscience. It analyzes how the principles that govern chance impinge on politics, business, traditional medicine, economics, sports, leisure, and other human affair areas.

Included in the book are graphs and tables to help enhance understanding.

Finally, there are a few example problems in this book that require the use of basic mathematics. All example problems are solved by the author. I found some of these solutions difficult to follow and this is my only complaint. I feel that the solutions to these example problems could have been laid out better. Diagrams would also have been helpful in these solutions.

However, it is not essential to understand these solutions to grasp the main points of this book.

In conclusion, I estimate that any potential reader will be entertained and learn something from this illuminating book!!

(first published 2008; prologue; 10 chapters; main narrative 220 pages; acknowledgments; notes; index)

<<Stephen Pletko; London, Ontario, Canada>>

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Given that I'm predisposed toward mathematical determinism, I found this book both insightful and thought provoking.

Coincidently, a few days after reading this book, in Jan 2009, the Nebraska Pick 3 Lottery had the same 3 numbers (out of 9) drawn in the exact same sequence two days in a row. The newspapers reported that this was a 'one in a million' chance. I attempted to use Pascal's triangle to calculate whether or not this was true and, not surprisingly, got stumped. My 'gut' said that no, this was much less than a 'one in a million chance'. So I did what any math geek (my words) would do and that was to email Professor Mlodinow (he included his email address in the jacket cover). Within a few days, he responded and confirmed my gut feeling. In fact, picking the winning combination the FIRST time was a one in a million chance but picking it again, was only a one in 1000 chance. It confirmed the basic premise of the book which is that things we think are random, may not be....just do the math.

Mlodinow shows two graphs comparing the performance of a large number mutual fund managers for a one year period and a longer period. The first graph shows that some did very well and some very poorly, with the rest in between. The second graph looks like noise. But if you look carefully at the two graphs you will see that a majority of those who did very well and of those who did very poorly in the first graph were also in those same groups in the second graph. Unless I am mistaken, that seems to contradict his argument that the managers do no better than chance. Otherwise the book is a very interesting read.

Great start and well written but never did quite take me down the paths I thought it might. I guess randomness dictated that too.