Richard Alpert was born in Boston on April 6, 1931, to George and Gertrude (Levin) Alpert. His father, a lawyer, was a founder of Brandeis University and president of the New Haven Railroad. Richard had a bar mitzvah but said he had no religious convictions as a youth.

A “spit and polish” son of a corporate executive, as he described himself, he graduated from Tufts University in Massachusetts as a psychology major in 1952 and studied for a master’s degree in the subject at Wesleyan, only to flunk the oral exam.

Nevertheless, Mr. Alpert was accepted as a Ph.D. candidate at Stanford and earned his doctorate, staying on afterward to teach. That was followed by twin appointments, in psychology and education, at Harvard.

He soon had an apartment full of exquisite antiques, a Mercedes sedan, an MG sports car, a Triumph motorcycle and his own Cessna airplane.

It was at Harvard that he crossed paths with Mr. Leary, who was lecturing there in clinical psychology. They became drinking buddies. Mr. Alpert admired Mr. Leary’s iconoclasm; he told the Tufts University alumni magazine in 2006 that Mr. Leary was “the only person on the faculty who wasn’t impressed with Harvard.”

While working at the University of California, Berkeley, Mr. Leary had done research on psilocybin, the main psychoactive ingredient in some species of mushrooms, and he continued the work at Harvard. Psychiatrists were interested in mind-altering drugs as clinical aids because they were thought to mimic schizophrenia, but Mr. Leary wanted to see if they could be beneficial.

He invited some friends — including Mr. Alpert and the poet Allen Ginsberg — to his house in Newton, Mass., on March 5, 1961, a Saturday. In his kitchen, he distributed 10-milligram doses of psilocybin.