Coincidences set up mental error

By Kimberly Patch, Technology Research News

Ever fix something using a specific remedy only to later realize that the fix had nothing to do with the problem resolving itself?

It may seem obvious after the fact that pushing a specific sequence of computer keys has nothing to do with avoiding an automatic eight-second delay, but because you were seemingly fixing the problem by taking a specific action the scenario made perfect sense at the time. This is because it was part of your working mental model.

Researchers from the Universities of Newcastle upon Tyne and York in England have showed that this psychological phenomenon -- a person's tendency to assume that a sequence of events are causally related if those events fit the mental model people construct to filter information -- can cause highly-trained operators to make high-consequence mistakes without noticing those mistakes.

The researchers are making human-computer interfaces designed to sidestep the problem. Such interfaces could lead to safer machines, including airplanes, according to the researchers.

Mental models are shortcuts -- simplified pictures of reality that help the brain cope with the complexity of the outside world. "Because the human brain does not have the capacity to process [every] single piece of information in our environment, it has to filter out what it does not want," said Denis Besnard, a research associate at the University of Newcastle upon Tyne. This explains the tendency to filter out surrounding sounds when reading an interesting book, he said.

Our limited processing capacity causes us to unconsciously aim for solutions that are good enough instead of perfect solutions, said Besnard. We also implicitly accept that we cannot understand everything in our environment, he said.

This cognitive economy strategy shapes reality into a distorted picture -- the mental model. "This picture is strongly influenced by our goals and we use it to decide about what is happening, [and] what will happen if we do this or that," said Besnard.

Although the model allows us to function in a complicated environment, it also harbors potential problems. "When something that we expect happens, we tend to believe that we understand the causes," said Besnard. In thinking we understand "we act under a confirmation bias whereby we rely on instances that confirm our predictions instead of trying to find the cases in which our expectations do not hold," he said.

Even operators in critical processes, like aircraft pilots, use these incorrect mental models, said Besnard. "Problems can then be felt to be understood when they are not... leading to mishaps and accidents," he said.

Coincidences become potentially dangerous in certain situations, given this mental phenomenon. Take a pilot trying to solve an engine problem by erroneously shutting off a correctly functioning engine at the same time as vibrations from a faulty engine subside, said Besnard.

The researchers examined such an instance that caused a British Midland Airways Boeing 737-400 to crash near Kegworth, England in 1989, killing 47. The vibrations were caused by a fan blade detaching from one of the plane's engines. According to the cockpit flight recorder, the flight crew wasn't sure which engine was affected, but throttled one of the engines back and eventually shut it down. The fumes stopped and the vibration dropped at the same time. "This co-occurrence led them to [wrongly] believe that they had solved the problem," said Besnard.

The crew decided to make emergency landing, and during the time they flew toward the airport the working engine showed an abnormal level of vibration for several minutes, but the flight crew did not notice the problem, according to Besnard. Only when they had begun the landing approach and the engine vibrations got much worse and were accompanied by a loss of power and an associated fire warning did the crew attempt to restart the other engine, and by that time it was too late.

The pilot and co-pilot survived and later said they had not remembered seeing any signs of high vibrations on the engine vibration indicators even though at least one of the pilots said he was in the habit of regularly scanning them.

A better understanding of the phenomenon promises to help design better interfaces for airplanes in order to allow pilots to more easily notice mistakes even when they correspond with the mental model phenomenon, said Besnard. "One of the things flight crews need to know is when they err," he said. "It seems obvious but it's not. Because of the complexity and tempo of the interaction aboard modern aircraft, pilots sometimes [make] mistakes they do not notice."

The researchers are currently looking at the conditions under which operators can lose their grasp on a situation, said Besnard.

The ultimate goal is to enhance the ergonomics of the cockpit, said Besnard. "This requires... a dialogue and collabora[tion], if possible, with cockpit designers," he said.

In general, modern cockpits should provide pilots with a picture of what is likely to happen in the near future and suggest solutions, said Besnard. "Pilots have too much data to process," he said. "Pro-active pilot-centered support systems... that provide feedback to pilots about events that may occur in the future and for which actions will be needed," would help, but have not been implemented in commercial aircraft, he said.

It will be between 5 and 10 years before the researchers' methods will be ready for practical use, partly because of the the complexity of the work, it's critical nature, and certification issues, said Besnard.

Besnard's research colleagues were David Greathead at the University of Newcastle upon Tyne and Gordon Baxter of the University of New York in England. The work appeared in the January, 2004 issue of the International Journal of Human-Computer Studies. The research was funded by the UK Engineering and Physical Sciences Research Council (EPSRC).

Timeline:   5-10 years
Funding:   Government
TRN Categories:  Human-Computer Interaction
Story Type:   News
Related Elements:  Technical paper, "When Mental Models Go Wrong: Co-Occurrences in Dynamic, Critical Systems," International Journal of Human-Computer Studies, January, 2004


February 11/18, 2004

Page One

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