Alternate Explanations

A key tool in our scientific toolbox is considering alternate explanations–in most cases, there’s more than one way that a given outcome could have arisen. As scientists, we need to consider all the different possibilities, instead of just going with the first one we think of (or that we like best). Only then can we start ruling out possibilities through research to figure out what’s really going on.

For each of the following correlational patterns of data, come up with, and briefly explain, at least three different causal explanations for them. There will probably be an “obvious” explanation–your gut response. But you should also consider reverse causation–could this actually happen in the opposite manner? (Keep in mind that this may not always make sense; you still should be able to explain this possibility.) Finally, you should also think about third variables–a separate factor that could be influencing both of these things.

(And by the way, just saying “there really isn’t a pattern” doesn’t count as an explanation; for each of these, let’s assume we have solid evidence that the pattern really does exist.)

Here’s an example to get you started:

The pattern is that people who consume more fish tend to have higher IQs.

One possible explanation is that eating fish will increase your IQ, because the nutrients in fish are good for brain development.

[Reverse causation:] Another possible explanation is that having a higher IQ will cause people to eat more fish, because individuals with higher IQs tend to be more aware of health information and are more likely to have heard about this correlation.

[Third variable:] A third possible explanation is that having more money causes both greater fish consumption as well as higher IQs; since fish is expensive, people with more money can eat it more regularly, and having more money also means you can afford more high-quality educational experiences that can increase IQ.

The pattern is that pet owners are more social than non-pet owners.

The pattern is that people who are more open to new ideas also tend to be politically liberal.
The pattern is that older adults tend to be happier than younger adults.
The pattern is that people who live in rural areas are more likely to own a gun than people who live in urban areas.