Last post, I covered two of the six most common mistakes people make in their thinking. Today I will cover the next two: appreciating the role of chance and misperceiving the world around us. Both of these are huge topics, so as Inigo Montoya said, “Let me ‘splain. No, there is too much, let me sum up.” 
3. We rarely appreciate the role of chance and coincidence in shaping events. Last time we discussed just how much people hate and misuse statistics. Another way our inbred antipathy for statistics comes into play is not understanding the role of chance. People seem to need to have a cause for everything. If something goes wrong, something must be to blame. We hate to admit that anything is left to chance (which, considering that quantum physics makes everything in the universe a probability, make explain why people don’t understand it). As even Einstein said, “God doesn’t play dice with the world.” However, given enough time or occurrences, even rare events occur. I once had a geology professor who told me that given enough time, events that are almost impossible become likely and rare events become commonplace. This is quite true, over enough time and with enough attempts, even the rarest events will happen. Sometime in your life, you are almost certainly going to see something that is incredibly, inconceivably rare. People talk about 1 in a million chances being so rare as to be inconceivable and not worth thinking about, but that chance happens to over 7000 people worldwide, it will happen to eight in New York alone. Occasionally, you will be among that 7000.
1 micromort = 1/1,000,000 chance of death. I’d be careful in that bathtub, if I were you.
Have you ever called someone only to find out they were trying to call you at the same time? I have done that with my wife. Many people invoke something mystical or a psychic connection that made us call at exactly the right time because surely, what are the chances of two people just happening to call each other at the exact same time? However, I talk to my wife on the phone far more often than I talk to anyone else. Considering the number of times that my wife and I try to contact each other, it is almost inevitable that sooner or later, we would try at the same time. There are those that seem to be consistently lucky or unlucky. If it were really just random chance, then it should all even out and everyone should be equally lucky (or not), right? Here again, with enough people, some people will just randomly be consistently luckier than others, no supernatural force required. There will always be outliers that don’t follow the typical pattern just through random chance.
You can see this same type of mistake when people incorrectly tie independent chances together. When flipping a coin, a string of 20 heads will do nothing to change the chance that the next flip will be heads or tails. This sort of mistake is often seen in gamblers and people playing sports in their belief of winning and losing streaks, in which the results of a series of chance occurrences is thought to affect the odds of future events. So how do we avoid this mistake? Never put much stock in one occurrence. Look at the accumulated data and weigh occurrences accordingly.
Probably one of the biggest fallacies people make in this regard is mistaking correlation for causation. Just because two events occur at the same time does not necessarily mean they are connected. Wearing a specific shirt when you win a game does not make it lucky. It will not influence the outcome of any other game except in how it affects your thinking. I can think of no better example of this than the Hemline Theory, which states that women’s skirt lengths are tied to the stock market. Sadly, despite such an absurd premise, it is still commonly believed and one can still find articles debating the merits of the hypothesis. Needless to say, even if they do tend to cycle together, it would be foolish to say that the stock market is controlled by what skirts women are wearing. What might be plausible is that both are influenced by some common factor. Thus, any study which claims to have found a correlation between two events or patterns has only taken the first step. Once a correlation has been found, it is then necessary to demonstrate how one affects the other. Often, it is found that there is no direct connection, but they may both be influenced by an altogether different factor. Check out the site Spurious Correlations to see almost 30,000 graphs showing correlations between totally random occurrences, such as the graph showing that increased Iphone sales are correlated with a drop in rainfall in Mexico, or that US STEM spending is associated with the suicide rate. How to avoid this problem? Look for multiple lines of evidence and a causal mechanism that explains how one could affect the other. Without that mechanism, you can only say that two things have something in common, you should avoid saying one thing caused the other until you can point to a direct connection.
Spurious Correlations. http://www.tylervigen.com
4. We sometimes misperceive the world around us. Many people make the assumption that that their eyes work like cameras, recording faithfully everything in their field of view and the brain accurately records everything that goes into it. Unfortunately, this is not true. Our senses are imperfect. They neither record all the information, nor does the brain provide a complete image of what is around you. Simply put, you cannot trust your senses. Magicians count on this. One of the best I have seen is Derren Brown, who uses a mixture of psychology and good old-fashioned stage magic to perform his tricks. Visual and aural illusions abound. Take our eyes for example. Unlike a video camera that records the whole scene within the confines of its lens at the same time. We put together images from fragments. We rapidly move our eyes all around our field of view in what are called saccades, focusing on one small bit, then another. The light enters the eye and is picked up by the retina, with rods detecting intensity of light and cones detecting color. Signals from these receptors do not enter the brain as a picture. They are filtered through specialized cells, some of which detect boundaries to sharpen focus, some detect movement, etc. All of these separate signals gets sent to the brain which puts together a patchwork image, an image with a lot of gaps. We don’t usually see these gaps because our brains fill them in with what past experience tells it to expect. This is a really important point. Past experience affects what we see. Our hearing works this way as well.
The fact that past experience affects what we see plays out in various ways. We overlook things that change between eye movements. We fill in the gaps with what we expect to see. Thus, how we view the world is in part dependent on what we expect to see and our expectations are based on our experiences. People with different experiences may view the same thing very differently. This happens so much that when we see something that does not fit our expectations, our brains can even go the point of overwriting the visual input with our prior expectations. And it gets worse. If we focus on something, this tendency to be blinded to other things increases. Most people have heard of ignoring the elephant in the room. A couple of researchers at Harvard did what they call the invisible gorilla experiment. People were asked to observe a group of people wearing shirts that were two different colors. They were told to count the number of times a ball was passed between members of the group wearing the same color shirt. Most people could successfully do this. However, many people missed the man in a gorilla suit who walked into the middle of the group, paused to look at them, and then walked off.
How could someone miss such an obvious thing? They were focused on the ball and missed the bigger picture. This problem is called selective attention or “inattentional blindness.”. This experiment has been done with hearing, in which the participants were to listen to only one of two conversations going on at the same time. This time, part way through, someone started saying, “I’m a gorilla,” multiple times. If just told to listen to the recording, everyone could hear it easily. But if told to listen carefully to only one conversation, most people never heard the gorilla. There are many, many examples like this of selective attention. This is exactly why eyewitness accounts in trials are not worth very much. You might hope it stopped at this level, but it doesn’t. Even if we accurately see what is there, our prejudices will affect our interpretation. Different colors affect our moods and perceptions. Religious or political beliefs affect our perceptions to the point we will literally see things differently, even our views of sports games. Space allows only a cursory mention here, but it is easy to find many, many studies, books, and shows that demonstrate just how unreliable our personal observations are. So how do we avoid this? To begin with, we recognize that our perceptions are fallible. Thus, the more independent observations we can make and the more people that observe it, the more likely it is to be valid. Take recordings that can be viewed and listened to at different times. Try this out for yourself. Watch a movie with other people. Have someone prepare a list of questions in advance about a particular scene. After everyone has viewed it, have everyone answer the questions on their own and then compare them. Most likely, you will find some things people answered differently, other things some people did not see at all. Or just listen to the responses from political leaders after any speech by any President. The best way to get around this problem is through multiple, independent observations. Never trust just one observation and always question the biases of the observer.
Next post we will wrap up this series with the last two common mistakes. Stay tuned.
paleoaerie 