RAMSEUR, N.C.

THE little house was awfully pretty, its corrugated metal cladding glinting in the sunlight, as honest and spare as a child’s drawing, amid ancient magnolias and overlooking acres of lush soybeans. The owners, Terrie Moffitt and Avshalom Caspi, two psychology professors at Duke, declared themselves delighted with it.

They admired the way the house embodied the rural architecture they loved: the dogtrot cabins of the American South and the “wrinkly tin” structures of New Zealand, where they are conducting a longitudinal study of 1,000 individuals. (Dr. Moffitt, 57, and Dr. Caspi, 52, are nature- and nurture-ists. Their work examines the role of environment and genes in human behavior, particularly antisocial behavior and depression.) Dr. Caspi recalled the shacks on the kibbutz he grew up on, and Dr. Moffitt pointed out how the house’s tiny footprint overlaid that of the original farmhouse built by her family here in the 1920s, and how potent the memories still are.

To be sure, the house does have its skeptics. There was the neighbor who exclaimed, “Honey, you’ve made a terrible mistake and built your fireplace outside of your living room.” (Dr. Moffitt told him, “It’s worse than that. There is no living room.”) And her father took a dim view of their building, as he put it: “a cross between a chicken house and a trailer.”

But the only review they really cared about was that of Stephen Atkinson, an architect with whom they had made an unusual bargain. Mr. Atkinson, who lives and works in Palo Alto, Calif., had given them the plans for the house — they were free, but with a caveat. For every change they made to his original design, he would charge them.