Ms. Warren, who said she began the study on the lookout for “cheaters and deadbeats,” quickly realized that the people she was studying seemed familiar. Her own family in Oklahoma had teetered on the brink of financial ruin. It is a part of the biography she discusses in folksy speeches across the country — her father’s unemployment, her mother’s effort to save the family home with a minimum-wage job, and how that wouldn’t be possible today, with minimum wage paying below the poverty rate.

The revelations from her bankruptcy research, by her account, became the seeds of her worldview, laid out in her campaign plans for everything from a new tax on the wealthiest Americans to a breakup of the big technology companies.

Yet as Ms. Warren’s candidacy has gained traction, critics have complained that she is too rigid and radical in her liberal ideas, dug in to a polarizing degree against others with differing views, and can come across as dogmatic and intellectually strident at times. Mr. Johnson, who admires Ms. Warren, describes her as “hard as nails.” Some Democrats worry that such perceptions make her seem too left-wing and hard to work with, and could make it difficult for her to build an Electoral College majority if she is the nominee.

But a look at Ms. Warren’s philosophical and political metamorphosis provides yet another perspective on her personality, revealing a woman who searched for answers and found something she had never expected, then altered her thinking accordingly.

As Mr. Westbrook put it, “She is really someone who is willing to learn and willing to be persuaded.”

Law and Economics

In 1979, Ms. Warren recruited her parents from her native Oklahoma to her home in the Houston suburbs to help babysit her two young children.

Then a professor at the University of Houston, she would be spending several weeks at a luxury resort near Miami, one of 22 law professors selected to study an increasingly popular discipline known as “law and economics.’’ One of its central ideas is that markets perform more efficiently than courts.