By ERIC NAGOURNEY
Dr. Richard S. Lazarus, an influential psychologist who charted the terrain of human emotion, most notably how people cope with stress, died on Nov. 24 in Walnut Creek, Calif. He was 80.
His death resulted from a fall, said officials at the University of California at Berkeley, where he taught for almost four decades.
Dr. Lazarus began rising to prominence in the 1960's, when behaviorists like B.F. Skinner held sway over psychology and explanations for human behavior were often pared down to rudimentary motives like reward and punishment. In that world, love or sadness existed, but were considered more ornament than underpinning.
''For decades, psychology under the reign of behaviorism ignored what went on inside the head,'' said Dr. Paul Ekman, a psychology professor at the University of California at San Francisco.
Dr. Lazarus was an unabashed promoter of the importance of emotion, especially what he described as the marriage between emotion and thought. His views put him at odds not only with behaviorism but also with a movement that began toward the end of his career: attempts to explain all human behavior by looking at the structure of the brain.
Of a disagreement with another researcher, he once wrote:
''He remains as dedicated as ever to the view that the study of behavior and mind is handicapped by the absence of knowledge about the brain. I would reverse his argument completely by suggesting that knowledge of the brain is not necessary for an adequate theory of the mind and, ironically, in light of his position, that a knowledge of brain function cannot be obtained without a sound theory of mind and behavior.''
A collaborator, Dr. Susan Folkman of the University of California at San Francisco, said Dr. Lazarus had disliked simple explanations.
''He was very opposed to reductionist approaches to understanding human behavior,'' said Dr. Folkman, co-author with Dr. Lazarus of a 1984 book, ''Stress, Appraisal and Coping.''
At the heart of Dr. Lazarus's theory was what he called appraisal. Before emotion occurs, he argued, people make an automatic, often unconscious, assessment of what is happening and what it may mean for them or those they care about. From that perspective, emotion becomes not just rational but a necessary component of survival.
Dr. Lazarus liked to take on topics like hope and gratitude. He was perhaps best known for his work on coping, gaining attention for studies that showed that patients who engaged in denial about the seriousness of their situation did better than those who were more ''realistic.'' He also found that stress often had less to do with a person's actual situation than with how the person perceived the strength of his own resources.
Dr. Lazarus and Dr. Folkman argued that when problems arise, there are two ways of coping. One is to try to deal with the problem directly. The other is to try to reduce the anxiety caused by the problem. Both, they said, are beneficial. Even false hope can help.
''Mildly depressed people are very realistic about themselves, too realistic,'' Dr. Lazarus once said. ''As you become depressed, you become aware of your defeats and start to feel hopeless. People who function well strive against odds because they hold on to hope.''
Richard Stanley Lazarus was born on March 3, 1922, in New York. He graduated from City College in 1942 and earned his doctorate at the University of Pittsburgh.
He wrote 13 books, five after he retired in 1991. One book, ''Passion and Reason: Making Sense of Our Emotions,'' was written with his wife of 57 years, Bernice Lazarus. In addition to his wife, he is survived by a son, David, of Pleasant Hill, Calif., a daughter, Nancy, of Orinda, Calif., and four grandchildren.
Even Dr. Lazarus said positive thinking had its limits. A seriously ill person may do better if he maintains hope, but he should not be so optimistic that he fails to seek medical care. Still, Dr. Lazarus once told Newsweek, ''a little fooling of yourself can be helpful.''