Expectation Bias


Years ago when I moved into a new neighborhood, I was exploring different routes to drive to my new house. After only a short while, perhaps even just a few days, a stop sign showed up at an intersection with another residential street on one of the routes I was beginning to favor. I believed it was new, but with so much new to me at the time, I wasn’t sure. Of course, as I continued to drive that route, I got accustomed to stopping at that intersection.

A few months later, I witnessed a minor traffic accident there. I hung around to offer my statement to the investigating police officer. I overheard one of the drivers explain with sincerity but also with incredulity, “Where did that stop sign come from? I’ve driven by this corner every day for years and it was never here before.” After conferring with the officer, I learned that indeed the stop sign had been installed during my first week in the area. This driver was so accustomed to that route with no stop sign, that even months later he failed to recognize that it was there.

Expectation bias is a powerful force. As pilots we must strive to avoid falling victim to its insidious dangers. I am certainly susceptible to expectation bias and work hard to overcome that tendency … not always successfully. Recently a gentleman sent in an OTA that we published. In the write up, he mentions his husband in the other seat. While I recognize and support these men’s rights, I am a product of a time when one’s spouse universally meant a person of the opposite sex.

So, fueled by that expectation bias and lack of further thought while under time pressures, when I encountered this item, I merely assumed that something had gotten bollixed up in the multiple transcriptions from original e-mail to final layout. So I changed “husband” to “wife.” It was quite disconcerting to have my error—and the insult it caused—pointed out to me; Messrs. Fernandez and Sternbergh have since graciously accepted my apologies.

Expectation bias hits us from all sides. It might be as innocent as insisting a product isn’t on the shelf after
its labeling changed. Or it could be as costly as missing a new stop sign on a familiar street. Of course, in the cockpit it can have potentially disastrous consequences, such as turning base from the same point on downwind so habitually that you do so even after Tower tells you to extend, and you find yourself cutting off final traffic and needing an avoidance maneuver—and a phone call.

I like to think I do pretty well recognizing and avoiding expectation bias in the cockpit. However, this little life lesson shows just how pervasive it can be. We’re just human. So, I’m going to double down my efforts to recognize and avoid expectation bias in every endeavor. Surely, if I’m successful outside of flying, I’ll be better equipped to ward off most any danger from expectation bias when I fly. So, hopefully, I’ll be a better, safer pilot for it. Plus, there’s the bonus of avoiding little fender benders at new stop signs.


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