Cognitive bias, heuristic, logical fallacy: hidden features of the mind

These terms come around a bit, and I wanted to get them clear in my head so I understood the difference.

Cognitive bias

Cognitive biases are predictable patterns of thought and behaviour leading to incorrect conclusions. Things like anchoring, where we are predictably led astray by the presence of a previous number we have seen.

Heuristic

A heuristic is a mental shortcut to solve common problems. Things like social proof, how if others seem to like something that’s a shortcut for "we’ll probably like it."

Logical fallacy

A logical fallacy is a flaw in our reasoning, leading to a faulty argument. Things like the sunk cost fallacy, where we will sometimes make ourselves unhappy in the future because of something we’ve already done that we can’t change. The logical step would be to choose the path that would make you happiest in the future regardless of any sunk costs up to now. Turns out that’s hard.

HT: You are not so smart

Published 31 Mar 2016

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The availability heuristic (and bias)

So the story goes, as told by Stephen Sigler, Nature May 1989: "The US military studied fighter planes returning from missions to try to improve their survival rate and were considering adding heavy armour to those parts of the plane that tended to show the greatest concentration of hits from enemy fire, until statisticians pointed out the fallacy of that argument. The more vulnerable parts of the plane were those with the fewest hits; planes hit there tended not to return at all. The single most vulnerable part, the pilot’s head, was without serious scar in the sample of planes that returned." It’s easy to draw correlations from what we see in front of us. But what we see usually represents just a small part of what has happened. Focusing on the evidence we can easily see at the expense of that we can’t leads to survivorship bias. To say it another way, when Bill Gates drops out of college and starts Microsoft it might seem like dropping out is a path to success for others too, but that ignores all the dropouts who didn’t create Microsofts and consequently you didn’t hear about. Silent evidence — the evidence that we don’t or can’t easily choose to consider — is a term from Nicholas Nassim Talleb. When trying to discover the veracity of the planes story I enjoyed Bill Casselman’s American Mathematical Society article on The Legend of Abraham Wald. The postscript points to some of the source behind the story including a mention of Stephen Sigler’s letter in Nature quoted above. I covered survivorship bias before, but I like this story so much I thought it was worth doing again.…So the story goes, as told by Stephen Sigler, Nature May 1989: "The US military studied fighter planes returning from missions to try to improve their survival rate and were considering adding heavy armour to those parts of the plane that tended to show the greatest concentration of hits from enemy fire, until statisticians pointed out the fallacy of that argument. The more vulnerable parts of the plane were those with the fewest hits; planes hit there tended not to return at all. The single most vulnerable part, the pilot’s head, was without serious scar in the sample of planes that returned." It’s easy to draw correlations from what we see in front of us. But what we see usually represents just a small part of what has happened. Focusing on the evidence we can easily see at the expense of that we can’t leads to survivorship bias. To say it another way, when Bill Gates drops out of college and starts Microsoft it might seem like dropping out is a path to success for others too, but that ignores all the dropouts who didn’t create Microsofts and consequently you didn’t hear about. Silent evidence — the evidence that we don’t or can’t easily choose to consider — is a term from Nicholas Nassim Talleb. When trying to discover the veracity of the planes story I enjoyed Bill Casselman’s American Mathematical Society article on The Legend of Abraham Wald. The postscript points to some of the source behind the story including a mention of Stephen Sigler’s letter in Nature quoted above. I covered survivorship bias before, but I like this story so much I thought it was worth doing again.

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