What the Dog Saw Part 3 of 4: Blowup
February 17, 2010 by dr. lam
When the space shuttle Challenger blew up in the sky over southern Florida 45 minutes into its voyage on the fateful day of January 28, 1986, a search for blame began. The slipshod policies of NASA and its prime contractor, Morton Thiokol, were clearly to blame. Thirty-two months later, the shuttle Discovery was redesigned and launched as a testament to that correction. However, the sociologist Diane Vaughan, in her book, The Challenger Launch Decision, argued “No fundamental decision was made at NASA to do evil.” She further states, “Rather, a series of seemingly harmless decisions were made that incrementally moved the space agency toward a catastrophic outcome.” What? No one was to blame? Perhaps. Even if Vaughan’s arguments are only partly correct, it raises a fundamental concern of how we as humans need to wrap up our understanding of failure by laying blame.
In the near disaster of Three Mile Island (TMI) nuclear-power plant in March of 1979, the president’s commission concluded that the result was of human error, particularly on the part of the plant’s operators. However, perhaps the story is not that simple. It all began with a blockage in the plant’s polisher, a giant water filter of sorts. Polisher problems are a relatively common occurrence and one that typically does not lead to any major problems. However, in this case, the blockage caused moisture to leak into the plant’s air system, which then tripped two valves that in turn shut down the flow of cold water into the plant’s steam generator. Typically, the backup cooling system handles such a problem. However, for a reason that is unclear, the valves for the backup system were closed. In addition, a repair tag hanging on a switch above the indicator just so happened to block the visibility of the off setting in the control room. That left the relief system to handle the problem. However, it just so happened that the relief system was not working that day. In addition, it just so happened the gauge to tell the operators in the control room that the relief system was not working was also not working. By the time that the operators figured out the 5 things that all went wrong at the same time, TMI was near hitting a melt down.
Charles Perrow of Yale University is a sociologist who has investigated these matters and has classified the accumulation of minor events that lead to catastrophe as a “normal accident.” In his classic 1984 treatise on accidents, Perrow uses examples of well-known plane crashes, oil spills, chemical-plant explosions, etc., to show that many of them can best be understood as “normal”. The most famous example of a normal and not a “real” accident is Apollo 13, as brilliantly depicted in the movie of the same name. The Apollo flight was hit with a combination of the failure of the spacecraft’s oxygen and hydrogen tanks and the failure of the astronauts to recognize the problem due to an indicator light that diverted their attention.
Was the Challenger accident then a normal accident? Not exactly. The Challenger failed because of one catastrophic problem, the O-ring. However, Vaughan looked at the culture of NASA that over decades had accepted what was deemed normal risk or deviance. This creep of behavior over time allowed the brass to accept the O-ring problem as within tolerable limits of normal. So it was not amoral or immoral individuals that ignored dangers, it was the longstanding culture of NASA to factor in this risk as part of conformed policy.
In fact, how we handle risk is something fascinating. When we become accustomed to risk, we start to behave a bit like NASA. Since the O-rings never caused problems in the past, then we can lower our standards a bit. This is known as risk homeostasis. The introduction of ABS brakes actually led to a higher incidence of accidents because people began to act erratically on the roads and took greater risks. The adoption of seat belts however was such a powerful factor toward safety that it overcame the limited increase in risk homeostasis. An example in Sweden is fascinating. In the late 1960s, Sweden switched from driving on the left hand side of the road to the right side. Instead of an increase of accidents, there was a decrease of 17% during the next year, followed by a steady return to previous accident levels. People were simply driving much more safely to avoid a possible accident.
What this chapter brought to my attention were several important ideas. First, we humans tend to ascribe blame to an accident because we want a reason for something and a story to tell it. However, sometimes accidents just occur no matter what we do to try to avoid them. Second, if we look less proximally at the accident but at the larger culture we may be able to create an environment that is less prone to having an accident. Finally, if we take even a deeper look at our own irrationality, we can see that our accustomed insouciance toward risk can be the ultimate cause for increasing our own risk, the so-called concept of risk homeostasis.
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Nice concept and something to contemplate! You summed it up very nicely, Dr. Lam! Thanks!
I always enjoy Malcolm Gladwell’s work, and consider his insights as brilliant exercises in lateral thinking. The Swedish driving piece, among others, has opened my conceptual thinking in my clinical practice:. When I’m asked about the validity of the Blood Type Diet by patients, I suggest that it’s a good concept, but if anything, the success from this is probably from the attendance to a healthy, relatively non-deprivational diet by individuals who otherwise might not have been so attentive to diet for health.