The movie "Taxi Driver" gave John W. Hinckley the idea of making his mark on life "in an unconventional way," but Hinckley wasn't imitating the movie's main character when he shot President Reagan, a government psychiatrist testified yesterday.

"I think John wanted to be known for what he did himself . . . He didn't want to be known as following Travis Bickle the taxi driver in the movie ," Dr. Sally A.C. Johnson told the jury yesterday in an unusual Saturday session of his trial. "I think he wanted to have some attention or fame that was John Hinckley's."

She said the movie, which defense psychiatrists have described as a driving force in Hinckley's life, was "only a model" for him.

Johnson, a staff psychiatrist at the federal correctional institution at Butner, N.C., interviewed Hinckley 55 times in the three months after the shooting. Yesterday she told the jury she believed that while Hinckley suffered from personality disorders when he fired on Reagan, he was nevertheless in control of his behavior and was legally responsible for his acts.

During her testimony, Johnson recited a list of factors she said supported those findings, including the fact that Hinckley had read about other assassinations and knew they were wrong, that he carried guns with him and stalked former President Carter and Reagan without shooting, and that he practiced at target ranges "to improve his skills."

Johnson told the jury that Hinckley showed a "logical reasoning process" when he picked his assassination target, basing his decision on how powerful he viewed the person to be. Hinckley, aware of Carter's decline in popularity, focused on president-elect Reagan after the 1980 election and, sometimes armed with a gun, waited for Reagan four or five times outside Blair House where he was staying before the inauguration.

"Even when he had a gun with him he was able to choose not to shoot," Johnson told the jury yesterday.

Hinckley's defense lawyers have presented expert psychiatric testimony that Hinckley, obsessed with actress Jodie Foster and driven by suicidal impulses, had withdrawn into an "inner world" of distorted emotions that eventually compelled him to fire on Reagan.

Yesterday however, Johnson disputed the defense theories, telling the jury that Hinckley's preparation for the shooting, his assessment of the scene when he arrived at the Washington Hilton, his internal debate about whether to fire the shots and his realization that he might "lose his life or his freedom" by his acts showed he was in control of his behavior.

"I don't get the sense of a person compelled to shoot the president . . . that wasn't the case with John," Johnson told the jury.

Johnson noted that while Hinckley saw Reagan enter the Hilton, he did not shoot at that moment. Instead, he left the area while Reagan was inside giving a speech, later returning to his place in a crowd of spectators and the media.

During interviews within five days of the shooting, Johnson said Hinckley told her when Reagan emerged from the hotel he thought to himself: "Should I, should I pull out the gun and start firing?" That, she said, showed his deliberation before he decided to fire.

In addition, Johnson said Hinckley told her he thought "there he Reagan is, I'll never get a better shot." She described those statements as suggestive of an assassination attempt, not suicide. Defense psychiatrists have testified that Hinckley was driven to shoot by a desire to end his own existence.

The letter Hinckley left behind in his hotel room for Foster set out his goals for criminal behavior and showed that he intended to make an attempt on Reagan's life "if the situation was right," Johnson testified. If he did go through with the act, Hinckley knew the letter would become part of the crime scene and tell people what he had been thinking, Johnson said.

Johnson testified that the letter showed Hinckley's overall interest in the "drama" of his plans, which she said he found "exciting." While Hinckley's defense lawyers were distressed when the letter was published in newspapers days after the shooting, Hinckley was glad, Johnson testified.

At the time of the shooting, Hinckley subconsciously wanted to "prove to himself that he could do something of this magnitude," Johnson testified. Hinckley also wanted to "get back" at people he felt had failed to meet his needs and let him down in the past, including his parents and a psychiatrist who treated him for five months before he attacked Reagan, she told the jury.

Johnson, questioned by Assistant U.S. Attorney Robert R. Chapman, disagreed with the defense psychiatrists' diagnosis that Hinckley suffered from forms of schizophrenia, a severe break with reality, or that he experienced extreme depression.

While Hinckley was bored, lonely and felt hopeless, those features do not amount to major depression, Johnson said of Hinckley, adding he never lost interest in his usual, albeit seclusive, activities, including writing, listening to music and playing the guitar, Johnson said.

Hinckley showed none of the features associated with schizophrenia, such as delusions, bizarre behavior, hallucinations, feelings that people were "out to get him" or hearing voices in his head, Johnson testified. Hinckley knew he had "problems," Johnson told the jury, but he never lost touch with the reality boundaries between himself, others and his environment.

"He functioned too well," to fit the pattern of schizophrenia, she said.