How Missed Details Led to the USS Vincennes Incident

290 people were killed in the 1988 USS Vincennes incident due to the captain’s failure to perceive the data available to him.


| September 2014



USS Vincennes

As the disastrous USS Vincennes incident showed, in high-stress situations we must rely upon sensory processing, rather than slower cognitive processing, to make decisions.

Photo courtesy Wikimedia Commons

In Coming to Our Senses (Oxford University Press, 2014), cognitive scientist Viki McCabe argues that our tendency to privilege cognitive processes over the information we access with our perceptual systems often leads to making inaccurate decisions based on oversimplified theories. Instead, we should rely on our sense of the structural organization of the world to accurately perceive the complex and interconnected systems that comprise our environment. The following excerpt from “The Structure of Reality” offers an example of a situation in which expectancy bias and failure to perceive structural data led to disaster.

"Only when the human organism fails to achieve an adequate response to its situation is there material for the processing of thought."—L. L. Whyte

The USS Vincennes Incident

At 9:54 a.m. on July 3, 1988, the U.S. Navy cruiser Vincennes mistakenly shot down Iran Air’s Flight 655, killing all 290 people on board. It was the ninth worst incident in aeronautical history and to make it even worse, the decision that led to these deaths was based on a theory of the situation rather than on supporting evidence. Here is a very brief recounting of how our mind can reframe reality.

When this incident began, the Vincennes was in Iranian territorial waters in violation of international law and had been mixing it up with several Iranian gunboats. At 9:47 a.m., a distant blip—an airplane lifting off from Bandar Abbas airport—was picked up by the Vincennes’ radar, whose crew responded immediately with a standard Identification Friend or Foe (IFF) query. They received a Mode 3 Commair response, which indentified the plane as a commercial airliner. But during the gunboat fracas circumstances on the Vincennes had become chaotic, and in the confusion the crew ended up providing mixed messages—one speculating that the blip could be an enemy F-14 fighter jet and another insisting the blip was a civilian plane.

“In the cramped and ambiguous combat environment of the Persian Gulf…the captain chose to rely on his own judgment.” He reportedly ran a simulation of the situation in his mind where he tried “to imagine what the pilot was thinking, what the pilot’s intent was.” His belief—that without direct evidence, we can nonetheless deduce what someone whom we do not know and cannot see is planning to do—could qualify as magic thinking. Yet without checking further, the captain developed the theory that the plane was an F-14 fighter and that it was diving directly at the Vincennes.

A simulation is not the situation itself. It is only a theory of the situation. A key point is that no one else actually saw this theorized threat. In fact, a crewmember standing right behind the captain later “testified that he never saw indications that the aircraft was descending.” Further, the commander of a nearby frigate, the USS Sides, reported that his radar showed an ascending, not a descending plane. That plane was not only much larger than a fighter jet, but it was also flying in Iranian airspace over Iranian territorial waters on its regularly scheduled twice-weekly flight from Tehran, Iran to Dubai, United Arab Emirates via Bandar Abbas, Iran. The radar-tracking systems of the Sides and the Vincennes both covered that same airspace. When the record of the Vincennes’ tracking system was later reviewed, the information it showed was found to be identical to the one from the USS Sides. How was it that the captains of these two ships reported seeing such different situations?