In analyzing the texts, the researchers found strong correlations between the content of people’s current lives and the stories they tell. Those with mood problems have many good memories, but these scenes are usually tainted by some dark detail. The pride of college graduation is spoiled when a friend makes a cutting remark. The wedding party was wonderful until the best man collapsed from drink. A note of disappointment seems to close each narrative phrase.

By contrast, so-called generative adults — those who score highly on tests measuring civic-mindedness, and who are likely to be energetic and involved — tend to see many of the events in their life in the reverse order, as linked by themes of redemption. They flunked sixth grade but met a wonderful counselor and made honor roll in seventh. They were laid low by divorce, only to meet a wonderful new partner. Often, too, they say they felt singled out from very early in life — protected, even as others nearby suffered.

In broad outline, the researchers report, such tales express distinctly American cultural narratives, of emancipation or atonement, of Horatio Alger advancement, of epiphany and second chances. Depending on the person, the story itself might be nuanced or simplistic, powerfully dramatic or cloyingly pious. But the point is that the narrative themes are, as much as any other trait, driving factors in people’s behavior, the researchers say.

“We find that when it comes to the big choices people make — should I marry this person? should I take this job? should I move across the country? — they draw on these stories implicitly, whether they know they are working from them or not,” Dr. McAdams said.

Any life story is by definition a retrospective reconstruction, at least in part an outgrowth of native temperament. Yet the research so far suggests that people’s life stories are neither rigid nor wildly variable, but rather change gradually over time, in close tandem with meaningful life events.

Jonathan Adler, a researcher at Northwestern, has found that people’s accounts of their experiences in psychotherapy provide clues about the nature of their recovery. In a recent study presented at the annual meeting of the Society for Personality and Social Psychology in January, Mr. Adler reported on 180 adults from the Chicago area who had recently completed a course of talk therapy. They sought treatment for things like depression, anxiety, marital problems and fear of flying, and spent months to years in therapy.

At some level, talk therapy has always been an exercise in replaying and reinterpreting each person’s unique life story. Yet Mr. Adler found that in fact those former patients who scored highest on measures of well-being — who had recovered, by standard measures — told very similar tales about their experiences.