Illusions and survivorship bias

Most of us have seen optical illusions. Often these are fun exercises. But why do we keep falling for such illusions? It is because our minds are seeing and interpreting the vision at the same time. The brain is using past experience to fill in the gaps and find reference points for what we’re seeing. Using these clues, the brain interprets the visual signals it is receiving. This is true even when we’re reading something. Often the first thought we have or the first implications we can think of, may not be the right way to think about the issue. Sonke Ahrens even says that the first idea we have may not be the best idea. In short, we must avoid the fallacy of illusions.

Survivorship Bias

The book “How to take Smart Notes” gives an interesting story to demonstrate survivorship bias. During the second World War, Abraham Wald, a Mathematician was asked by the Royal Air Force (RAF) to find places in the plane that was being shot (by bullets) the most so as to increase armour protection for it. Instead of counting bullet marks on the planes as most of the others however, he proceeded to suggest them to armour the areas which did not have any marks.

The idea is that the reason the planes got back in one piece were because they weren’t hit in those critical areas (such as the fuel tank). The other places could take bullet shots and still survive. The planes that did get shot in those critical areas never made it back so the others couldn’t realize it. This is what we call survivorship bias. The others had fallen prey to the fallacy of survivorship bias. Wald didn’t.

Learning requires effort

Here is the insight that I derive from the previous two ideas. Learning from mistakes is a lot more than an inspirational quote. It is a skill that requires practice. In other words, we need to work hard not to fall prey to survivorship bias. And the first thought that we get when we read could be misleading. How do we tackle it?

Writing down our thoughts and ideas can help us compare different ideas. It can help us see the holes in our arguments clearly. It can help us draw conclusions and analyse them. In short, any form of serious learning needs the external scaffolding of writing – so as to not fall prey to survivorship bias or to the illusions of first impressions.