Distinguishing singular causation (A caused B) from general causation (X tends to cause Y).
This course has so far only discussed general causation, which can be demonstrated through randomized controlled trials and to a weaker extent Hill's criteria. But personal, policy, and legal decisions often depend on singular causation as well. It also sometimes matters whether the causation is by commission or by omission. The famous Trolley dilemma is discussed.
After this lesson, students should
Singular Causation
General Causation
Omission Bias
Status Quo Bias
Drug Trials
Weather and Climate Change
This drug will absolutely cure you, because there was a really big RCT that showed it works for your exact disease!
| 5 Minutes | Introduce the lesson and go over the plan for the day. Make sure people have groups, spokespeople, etc. |
| 35 Minutes | Guide the students through the singular and general causation discussion questions. |
| 15 Minutes | Discuss the trolley problem example. |
| 25 Minutes | Go through the life saving treatments discussion. |
Have your students discuss the following questions in small groups. Each question and sub-question should take around five minutes.
Which kind of causation can an RCT establish?
General causation. The purpose of an RCT is to average away all the nuances that arise from the singular cases of the individuals in the trial.
Suppose we conduct an RCT that determines salt causes heart disease. Suppose Sally is in our study, has a high level of salt, and contracts heart disease. Did Sally's salt intake cause her heart disease?
It's impossible to say for sure. All we really know is that Sally was more likely to develop heart disease than someone with less salt intake. In this way the trial is suggestive that the salt intake played some role in causing her heart disease. But, that's all our trial tells us.
On January 4, 2022, a federal inquiry into the Dixie Fire of August 2021, the second largest wildfire in California history, determined the wildfire began when a tree came in contact with a power line operated by PG&E.
Is this a statement of singular or general causation?
Singular causation.
It is well established that climate change increases the number and intensity of wildfires in California. Given this known fact, why did the federal investigation not immediately conclude that climate change was the cause?
Although climate change tends to result in worse wildfire seasons, it has to do this via some mechanism. It can lead to hotter weather and drier foliage. This doesn't cause fires directly but increases the likelihood that other things that tend to start fires actually end up doing so. Identifying which mechanism was the singular cause of this fire can help us find additional general causes (such as uncleared foliage and unmaintained infrastructure) that work in conjunction with climate change.
PG&E has faced criminal charges from multiple California counties for the role of its equipment in causing wildfires. When determining guilt or innocence, does the legal system typically focus on singular or general causation?
The legal system typically punishes acts of singular causation. However, this is done with the intent of discouraging future acts. In this way, it acts generally as well. Class action suits can involve general causation, as when a toxin causes cancer in some but not all people exposed.
Assume you're in charge of creating policy to prevent California wildfires like the Dixie Fire from happening in the future. What are some policies that might have prevented the Dixie Fire? Does policy making typically focus on singular or general causation?
Policies to address climate change and increase infrastructure standards would help prevent cases like the Dixie Fire. These focus on general causation. Even policies that increase the punishment for having roles in starting fires are ultimately addressing general causation as well, since they aim to have a broad impact.
Why do you think it is so tempting to assume that each event has a singular person or entity to blame? When is this useful or not useful?
One possible reason is that it's much easier to think about and deal with singular entities because it's simpler to intervene on one entity than on many. Additionally, we tend to over perceive the effects of individual agents, which are singular factors. This could be because they are more important to notice in the short term. For example, it is more important to notice an enemy that tripped you than a series of small factors that led to you being tripped. And, as previously noted, the former is easier to act on.
The point of the trolley problem is to emphasize the effect of omission bias. In doing so, it shows the different weights society and individuals tend to put on acts of commission versus acts of omission.
If you deem it appropriate, you can show this clip from the show The Good Place.
The clip has some violence and gore. You may want to provide a disclaimer before showing it.
In small groups, have students discuss the following questions:
Bring the students back and have them share what they talked about. Then explain a hypothetical scenario where you are a doctor in a hospital where there are five sick people whose lives could be saved using the organs of one healthy person, who will die when their organs are taken. Have the students discuss the following questions:
Then introduce "omission bias," which is the human tendency to favor an act of omission (inaction) over one of commission (action). For example, people give more blame to bad consequences of action than bad consequences of inaction; people give more credit for action with good consequences than inaction with good consequences. It is one explanation of the status quo bias, in that people prefer not to actively change the current situation, even if the change is more likely to result in a good outcome. The omission bias itself is not necessarily rational or irrational.
Finally, provide this real world example. Here, "subjects are reluctant to vaccinate a (hypothetical) child when the vaccination itself can cause death, even when this is much less likely than death from the disease prevented."
Suppose there is an emergent disease in a population. If left untreated, 1 million people will die from it. A new vaccine is available with 100% effectiveness in preventing the disease. However, if the whole population were vaccinated, then an estimated 100 people would die as a result of adverse reaction to the vaccine.
