The Drunkard’s Walk: How Randomness Rules Our Lives by Leonard Mlodinow
The Drunkard’s Walk: How Randomness Rules Our Lives (Vintage)
I’m going to admit up front that I had a tough time getting through this book and ultimately gave up before finishing it. It’s not bad or poorly written, rather it discusses the history of statistics in depth. Coincidentally, at this time, I’m studying for actuarial exams and this was a little too much mental overload for me.
Summary:
The thought processes of individuals are seriously flawed when chance is involved. The human mind is build to accept that everything has a cause and thus it has a difficult time dealing with random factors. The title The Drunkard’s Walk comes from a mathematical term for random motion. The goal of this book is to illustrate the role of chance in the world around us.
Random events and our responses to those events determine our fate. Life is hard to predict and hard to interpret. When we use our habitual ways of thinking, we can come to solutions that are less than optimal. The human response to uncertainty is quite complex. The fear portion of the brain is activated when making a decision couched in uncertainty.
In any series of random events, an extraordinary event is likely followed by an ordinary or normal event. People’s intuition about randomness often fails them. When it came to random processes, people’s belief and intuition very often let them down. At this point, the author includes many studies and examples to highlight this point.
A lot of what happens to people in life is based on a combination of random factors and skill. The link between our individuals actions and the outcome of those actions is not as direct as we’d like it to be. We often underestimate the effects of randomness. Chance events are often misconstrued as accomplishments or failures. Random events come in groups, streaks, and clusters. These clusters are often misinterpreted and acted on. Again, the author includes several examples and studies to highlight these tendencies.
To understand randomness, you must first understand probability. The probability that 2 events will both occur can never be greater than the probability that each will occur individually. If the details we are given fit our mental picture, the more real it seems and the more probable it seems to be. However, the more details added to the conjecture make it less likely to happen. A good story is always less probable than a less satisfactory explanation.
People have poor memories when estimating the frequency and probability of specific occurrences. It is called the availability bias. In reconstructing the past, we give unwarranted importance to memories that are the most vivid and therefore the most available for retrieval. It distorts our view of the world by distorting our perception of past events and the world in general.
Then the author goes into a very lengthy discussion of: probability, the history of probability, calculus, and other mathematic topics such as limits, law of large numbers, sample spaces, conditional probability etc. The conclusion is that our brains are just not wired to do probability problems very well.
The chances of an event depend on the number of ways it can occur. This has a large effect and can be difficult to calculate and factor into a probability problem. The entire book looks at the world through the lens of mathematics and says that randomness is really the clash between the logical proof and the proof of the senses.
When we observe a relatively small number of outcomes, we tend to infer information and make judgments about the qualities that lead to those outcomes. Numbers always seem to have the air of authority. The book then goes on to discuss standard deviation, normal distribution, etc.
I really wanted to enjoy this book, but it just didn’t totally capture my interest. Hopefully based on my summary, it might prove to be more interesting to some of you out there.
