Every once in a while, we hear someone say “autism didn’t exist before vaccines” or “so many people are depressed, this rarely happened a couple of hundred years ago”. And while sometimes such phrases might seem to have a point, often times it’s nothing more than a logical fallacy.

Some Tumblr users gathered for a discussion around the topic, addressing the fact that many people who share the “mental illness is a trend” type of wisdom, forget some very crucial details.

Tumblr users jumped right into a discussion connecting survival bias with people claiming that many illnesses are “modern”

Image credits: Marco Verch

It is similar to the WWII aircraft situation, where statisticians had to analyze data of the damaged planes that returned from the field and determine which parts to improve. They looked at the diagrams and decided that parts showing most damage needed to be improved and protected. Seems logical, right? However, a Hungarian mathematician Abraham Wald spotted the error in their thinking, pointing out that the statisticians were looking at the damage to the planes that made it back, not those who were lost to enemy fire. Which means that the most damaged areas simply showed that the plane survived when taking hits to those places. What they were missing were the areas that showed minimal or no damage as those were where planes that didn’t return took critical damage. That is one of the best examples of survival (or survivorship) bias.

Survivorship bias refers to a phenomenon where one focuses on the people or things that made it past a certain selection process and overlooking those that did not. That often leads to overly optimistic beliefs because failures are ignored. Tumblr uses argue that the survivorship bias is to blame for many arguments people nowadays use against modern medicine and social changes.

Someone then offered a more in-depth explanation of the phenomenon

While many people like to point out that a term such as autism didn’t even exist “back in the day”, they fail to see that just because the term didn’t exist, that doesn’t mean that people with neurodiversity didn’t. The term itself was adopted in 1938 by Hans Asperger and medical records show that descriptions of various symptoms were recorded long before autism was named.

Image credits: pxhere

One person contributed to the discussion by offering a different opinion