See also: Hack Away at the Edges.

The streetlight effect

You've heard the joke before:

Late at night, a police officer finds a drunk man crawling around on his hands and knees under a streetlight. The drunk man tells the officer he’s looking for his wallet. When the officer asks if he’s sure this is where he dropped the wallet, the man replies that he thinks he more likely dropped it across the street. Then why are you looking over here? the befuddled officer asks. Because the light’s better here, explains the drunk man.

The joke illustrates the streetlight effect: we "tend to look for answers where the looking is good, rather than where the answers are likely to be hiding."

Freedman (2010) documents at length some harms caused by the streetlight effect. For example:

A bolt of excitement ran through the field of cardiology in the early 1980s when anti-arrhythmia drugs burst onto the scene. Researchers knew that heart-attack victims with steady heartbeats had the best odds of survival, so a medication that could tamp down irregularities seemed like a no-brainer. The drugs became the standard of care for heart-attack patients and were soon smoothing out heartbeats in intensive care wards across the United States.

But in the early 1990s, cardiologists realized that the drugs were also doing something else: killing about 56,000 heart-attack patients a year. Yes, hearts were beating more regularly on the drugs than off, but their owners were, on average, one-third as likely to pull through. Cardiologists had been so focused on immediately measurable arrhythmias that they had overlooked the longer-term but far more important variable of death.

Follow-up to: Heuristic is not a bad word

When I was in high school, I wanted to compose music. I wanted to write the music that I wanted to hear. There was only one problem: I have good aural imagination, but I don't have world-class aural imagination. I can look at sheet music and hear it in my head. I can hear chords. I can hear two-part harmony. Yet my aural imagination wasn't developed enough to generate novel music, except when I was in certain moods or about to fall asleep. And most of what I could hear in my head I found impossible to transcribe.

Nevertheless, I wanted to write cool music. I know what I like when I hear it. I had the ability to critique music; the only problem was creating it. So I developed my own technique for writing music: I composed using brute force. Before I describe how this worked, and how successful it was, I would like to talk more generally about brute force as a method for problem-solving.