Counterfactual – adjective: thinking about what did not happen but could have happened; contrary to fact or what actually occurred.
Example: If I hadn’t eaten that chocolate yesterday, would I have this migraine today?
In the context of research, which is my area of expertise, the counterfactual is the condition in which treatment is withheld. In an (randomized) experiment, the goal is to compare what happened to the group which received a treatment and the group that did not (i.e., the counterfactual). This provides an estimate of the treatment effectiveness.
The reason I chose the name The Counterfactual Brain for my blog is that I spend so much of my time considering what could happen with my migraine symptoms if I choose to do something differently or whether something might not have happened if I had chosen to do something differently. I often wish I could clone myself, live out both options, and see which scenario – if either – results in the broken vs. healthy brain.
You can read more about this in my first blog post “Introductions.”