Any real world situation can be a real mess to explain. In the first post in this series, I used the April, 2010 explosion of a BP oil rig and the massive oil spill that followed as an example. As people struggle to explain what happened, they say things like, "A buildup of gas caused an explosion on the oil rig, which causeddamage to the cap on the well. That damage to the cap allowed oil to spew from the well. A blowout preventer that could have sealed the well was prevented from operating properly because of damage from the explosion, or faulty installation, or a dead battery in a key component, or all of these factors combined.

How are people able to understand complex explanations like this?

This issue was explored in detail by Phil Wolff in a paper in the February, 2007 issue of the Journal of Experimental Psychology: General. He argued that people think about causes as if they were forces that move events in psychological space. To understand how this works, let's look at the explanation I just gave in more detail.

When we say that some event causes an effect, we mean that we do not think the effect would have occurred on its own. Instead, some force acted on the world to move events in a way that led the effect to happen. So, the cause provides a force that leads events in the world to move in a new direction.

In the oil rig example, most oil rigs do not explode or spew oil into the ocean. Instead, the gas buildup in the well provided a causal force leading to an explosion.

When we say that some event allows an effect, we mean that there is already some tendency for that effect to occur, and event fails to block the effect from happening. So, the event could have provided a force against the effect, but it does not.

In the BP example, the oil in the well is under pressure, and so it wants to emerge from the hole that created the well. The cap on the well normally prevents the oil from spewing out. When the cap was destroyed in the explosion, the absence of the cap no longer prevented the oil from emerging, and so it began to flow out of the well at a high rate.

When we say that some event prevents an effect from happening, we mean that there is normally some force that is likely to lead the effect to occur. The preventing event provides a second force that counteracts the event and keeps it from happening.

In our example, the blowout preventer normally seals the well in an emergency. A series of flaws and errors got in the way of the normal operation of the device, and so it did not seal the well.

Thinking about all of these causal forces helps us to combine elements of an explanation as well. For example, once we know that the damaged cap allowed the oil to flow and that the blowout preventer was unable to work because of damage, we can combine these parts to better understand the explanation. We can see that the oil continues to spew out of the well because a second factor that would have prevented it (the blowout preventer) was unable to operate, and so oil was allowed to continue to flow into the Gulf of Mexico.

Phil Wolff's research shows that people are quite good at recognizing these kinds of causal situations and combining them together to better understand more complex events. This work demonstrates that people naturally view events with an eye toward providing an explanation for why they happened. That is, you do not have to engage special thought processes to create a causal explanation of an event. It is an automatic part of the way you view the world that you begin to explain what is happening to yourself.

In the next post, I'll talk about differences in causal knowledge between humans and other animals.