On January 8 1989, British Midland Airways Boeing 737 was cruising at 28,000 ft when a strong vibration shook the plane. Fumes and a burned smell led the crew to believe that one of the engines was malfunctioning. When they throttled back the right engine, the vibration stopped, so they concluded that the right engine was the problem and they shut it off.

However, the left engine was the malfunctioning one; the reduction of vibration was only coincidental, something that the crew failed to notice. The left engine eventually failed completely during their final approach, and the plane crashed with neither engine running, killing over 40 passengers.

Dealing with complex problems, we face blurry situations where it’s unclear what the problem is, what potential answers are, and how items of evidence fit in. In fact, evidence is often compatible with several hypotheses, which may make it easy to reach the wrong conclusion. One way to regain some control is to fully disclose your thinking; mapping it can help you do so.

To improve your thinking, graphically disclose it, entirely

When discussing the scientific method, Gauch argues that we should expose our entire thinking. In his words: “at most, a scientific argument may be correct; at least, it should be fully disclosed. Full disclosure is the first and minimal requirement for clear scientific reasoning.” (Gauch, 2003)Mapping your thinking can help you fully disclose your thinking—to others and to yourself. Twardy has shown that mapping can help us improve significantly our critical thinking (Twardy, 2010)

On that fateful day, the crew’s thinking went something like this: When we throttle back the right engine, the vibration stops, therefore there's a problem with the right engine, let's shut if off.

However, there is a second part to that reason that isn’t apparent. A hint that the thinking is not fully disclosed is that reasons always have at least two distinct claims while this one only has one. Fully disclosed, the argument might look like this:

[IMAGE MISSING: mapping-2.jpg]
Argument mapping / hypothesis mapping may help us understand our thinking in full, thereby helping us identify potential weaknesses.