Psychologists who studied the downing of an Iranian civilian airliner in the Persian Gulf say the military needs to better understand stress and should spend more on psychological research and improve its crew training.

The judgment of the Navy cruiser crew that mistakenly shot down the Iranian plane July 3 was clouded by misconceptions caused by stress, the psychologists said."There is much knowledge about how decisions go wrong and how they can be improved that is not being put to use in military decision-making," Dr. Paul Slovic, a psychology professor from the University of Oregon, told a House panel Thursday.

Dr. Steven Zornetzer, representing the Navy's office of naval research, responded that the service does try to consider stress and is spending $12 million a year on basic research into psychological questions. Another $18 million is being spent to apply the results of that research to Navy programs.

While progess is being made "it must be clearly recognized that these research problems are among the most difficult and complex in the entire research spectrum."

The hearing by the House Armed Services policy subcommittee was part of the panel's examination of the destruction of Iran Air Flight 655 that killed all 290 people on board. It was shot down by the cruiser Vincennes in the mistaken belief that the commercial jet-liner was a military plane diving toward the Vincennes.

A Navy investigation attributed the incident to stress-related mistakes made by the crew of the Aegis-class cruiser, one of the Navy's most sophisticated warships.

The Navy said crew members, under battle-caused stress after just finishing a firefight with Iranian gunboats, misread or misinterpreted a variety of electronic data from the Aegis computers.

Rep. Les Aspin, D-Wis., chairman of the panel, said, "Misinterpretations of data provided by the Aegis weapon system and chaotic communications in the command center have pointed up troubles with man's ability to make fast, accurate decisions in combat."