Information Cascades and Common Misconceptions
http://en.wikipedia.org/wiki/List_of_common_misconceptions
The other day I found myself reading the above Wikipedia article about common misconceptions. This alone is not noteworthy, I often find myself clicking through Wikipedia when I should be doing much more useful things. However, this time I realized that each misconception I was reading is a direct result of an information cascade.
More generally, I realized that society uses information cascades to spread information while minimizing each individual’s cost in terms of wasted time, resources, and effort. Furthermore, the higher the cost of independently obtaining some piece of information, the more likely an individual is to come to a conclusion based on the testimony of others.
For example, consider the following accurate bit of driving advice: you should turn your wheels towards the center of the road when parking on a steep hill while facing upwards. Driving instructors will often prove this tip by reasoning that if your car slips out of gear, your front wheels will almost immediately collide with the curb. If their students do not believe them, they simply have to drive up a hill and let off the gas to give it a try. Note that this example does not use an information cascade because the students were given more than just the conclusions that previous drivers reached. In fact, it can be said that they each independently investigated the driving tip by expending the time and effort needed to reason through the instructor’s proof and perhaps to give it a try.
Next consider the following bit of medical advice: never feed your dog dark chocolate because it is poisonous. Any vet will tell you that this statement is true, but how could the average individual determine this independently? One method would be to simply feed dark chocolate to their dog, but the cost of that approach is obviously too high. Another would be to try to research studies addressing this issue, but that would require more time and effort than the average person would be willing to invest. Faced with no low-cost alternative, the average person simply examines the conclusions that their peers have reached, taking part in an information cascade.
Returning to the Wikipedia article, we can see that each example of a common misconception has a similar set of circumstances to the previous example. To individually investigate them, one would have to commit to a detailed search of the historical record or become educated in various fields of science and math. Clearly the average individual will not invest the time or effort needed to do these things, leaving them with information cascades as their source of knowledge. It just happens that in the case of common misconceptions the crowd isn’t right, resulting in the continued propagation of a misconception.