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Flight Lines: Pitfalls of perception and expectations

How is it possible to mistake this great egret for a small perching bird like a loggerhead shrike? It happens. Keith Corliss / Forum Communications Co.

Reality can be an elusive thing, or at least our perception of it. I'm no psychologist but I am well aware that what we think we see or hear might be light years apart from what is actually taking place. Defense attorneys will tell you the same thing but with considerably different motives I suspect.

No more clearly was this demonstrated to me than when I attended the Air Force's Flight Safety Officer School in southern California back in 1988. Most intriguing for me were the various aspects involved with accident investigation. Even more interesting than metallurgy and aerodynamics was the loosely defined group of elements lumped under the heading of "human factors." The human animal and its interaction with complex systems, we were to learn, is a highly dynamic affair involving multitudes of emotions, cognitive abilities, and mental and physical limitations. One such limitation is perception.

The instructor for this particular phase was an ex-Marine fighter pilot, now a psychologist. He began one day with the showing of a brief video clip to our class of about 25 students. It depicted a fairly innocuous scene of an urban street with vehicles and people going about their daily business. Three minutes later he shut the movie off and issued a short quiz. What was the color of the taxi cab? What kind of hat was the man on the step wearing? What object was in the hand of the woman with the dress? And other such harmless queries.

Once the answers were turned in the discussion began. And it became quite heated. We were young, capable, confident military pilots and no one was going to tell us we were wrong. Of course our answers to the questions were all over the map ('it was a yellow was a checkered was a white cab') but that didn't stop each of us from vigorously defending our answers. "I know what I saw," was a common and confident utterance. Once the video was replayed, however, a stunned silence hung over the room. As it turned out none of us had answered all the questions correctly, some not even close. This became the singular moment I realized eyewitness accounts are iffy at best.

Further clouding reality is the notion of expectations. Some might refer to it as the power of suggestion. And it commonly plays out in the bird-watching world. World renowned bird expert David Sibley confessed to the lure of expectations on his blog ( some years ago when in South Carolina he "saw" a loggerhead shrike, a rare bird for that area. It turned out the shrike was, in reality, a great egret.

A couple weeks ago it happened to me and a friend. We were in Maine's western mountain area looking for a particular species neither one of us had seen - Bicknell's thrush. This was a bird which sounded a lot like a close relative (gray-cheeked thrush) but occupied a higher altitude niche. We began climbing a ski slope in the pre-dawn hours in hopes of at least hearing this northeastern specialty. Nearly immediately we heard what we both thought was the song of the bird. Its song, repeating in the dark, even included some surefire notes which separated it from the gray-cheek's song. We were ecstatic. We were also wrong.

Having become so target-fixated on this one bird we had allowed ourselves to ignore contrary evidence. The song we were hearing was that of an Eastern towhee, a completely unrelated bird.

Sibley was one of the first individuals to question the identification of the celebrated ivory-billed woodpecker sighting in Arkansas in 2005. To this day the presence or absence of the bird remains a subject of emotional debate. Regardless of where one stands on the issue, Sibley does us all a service by piercing the murky mess with insightful words on perceptions and expectations.

"No intentional falsification or fabrication is needed, simply a subconscious selection of evidence supporting the favored conclusion, and a subconscious omission of refuting evidence. This generates false confidence. Once the perception is formed and "confirmed" it becomes nearly immune to question or revision."

This could fit well into a law school text book. But more to the point, it should also serve as a jarring warning that what we perceive through our senses may not always match the truth.