Density Curriculum

Section 3—Lesson 11: What Does it Mean for Density to Have Multiple Contributing Causes?

Background Information

Reasoning About Multiple Possible Causes

People tend to have difficulty reasoning about multiple contributing causes. They tend to make a couple of errors. They often look for one cause and then forget to search further. In some cases, that is enough—there is one cause and it is the only cause. However, it is possible that the one cause that they came up with is sufficient but not necessary for the outcome. This means that other causes can produce the same result. There can be multiple sufficient causes. For instances, there are multiple ways to be nominated for a public office, any one of which is sufficient to get a candidate's name on a ballot. In addition, one cause can be necessary but not sufficient to explain an outcome. This means another cause is needed to explain what happens. For example, a traffic jam can have multiple contributing causes where if any one single cause was missing, the jam might not result.

People also tend to search only for obvious causes. This can result in missing more subtle or non-obvious causes. In the case of density, looking for obvious causes leads us to miss phenomena that are density-related. This lesson actively engages students in thinking about multiple causes and why it is important to pay attention to them.