Mental Models and Normal Errors in Naturalistic Decision Making

“On a beautiful night in October 1978, in the Chesapeake Bay, two vessels sighted one another visually and on radar. On one of them, the Cost Guard cutter training vessel Cuyahoga, the captain (a chief warrant officer) saw the other ship up ahead as a small object on the radar, and visually he saw two lights, indicating that it was proceeding in the same direction as his own ship [Figure 1(t1), top panel]. He thought [emphasis added] it possibly was a fishing vessel. The first mate saw the lights, but saw three, and estimated (correctly) that it was a ship proceeding toward them [Figure 1(t1), bottom panel]. He had no responsibility to inform the captain, nor did he think he needed to. Since the two ships drew together so rapidly, the captain decided [emphasis added] that it must be a very slow fishing boat that he was about to overtake [Figure 1(t2), top panel]. This reinforced his incorrect interpretation. The lookout knew the captain was aware of the ship, so did not comment further as it got quite close and seemed to be nearly on a collision course. Since both ships were traveling full speed, the closing came fast. The other ship, a large cargo ship, did not establish any bridge-to-bridge communication, because the passing was routine. But at the last moment the captain of the Cuyahoga realized [emphasis added] that in overtaking the supposed fishing boat, which he assumed was on a near-parallel course, he would cut off that boat’s ability to turn as both of them approached the Potomac River [Figure 1(t3), top panel]. So he ordered a turn to the port [Figure 1(t4), top panel]. This brought him directly in the path of the oncoming freighter, which hit the cutter [Figure 1(t4), bottom panel]. Eleven coastguardsmen perished.”