(also known as: regressive fallacy)
Description: Ascribing a cause where none exists in situations where natural fluctuations exist while failing to account for these natural fluctuations.
A occurred after B (although B naturally fluctuates).
Therefore, A caused B.
I had a real bad headache, then saw my doctor. Just by talking with him, my headache started to subside, and I was all better the next day. It was well worth the $200 visit fee.
Explanation: Headaches are a part of life, and naturally come and go on their own with varying degrees of pain. They regress to the mean on their own, the “mean” being a normal state of no pain, with or without medical or chemical intervention. Had the person seen a gynecologist instead, the headache would have still subsided, and it would have been a much more interesting visit—especially if he were a man.
After surgery, my wife was not doing too well — she was in a lot of pain. I bought these magnetic wristbands that align with the body’s natural vibrations to reduce the pain, and sure enough, a few days later the pain subsided! Thank you magic wristbands!
Explanation: It is normal to be in pain after any significant surgery. It is also normal for the pain to subside as the body heals — this is the body regressing to the mean. Assuming the magic wristbands caused the pain relief and ignoring the regression back to the mean, is fallacious.
Exception: Of course, if the “cause” is explained as the natural regression to the mean, then in a way it is not fallacious.
My headache went away because that’s what headaches eventually do — they are a temporary disruption in the normal function of a brain.
Fun Fact: Seeing a doctor can have a real effect on pain relief, even if the doctor does nothing but provide a sympathetic ear. This is known as the psychosocial context of the therapeutic intervention and is often considered part of the placebo effect.
Poulton, E. C. (1994). Behavioral Decision Theory: A New Approach. Cambridge University Press.