The act of conversation has always had an architectural framework. In ancient Rome, the triclinium—a small dining table surrounded on three sides by couches—was a dedicated space for food and talk. Chilly medieval houses added benches next to a central fireplace to create nooks for intimate conversations. Arts and Crafts designers in England and the United States adapted these “inglenooks” in late-19th-century cottages. As modern central heating made toasty alcoves unnecessary, 20th-century house planning blended functions across large continuous rooms. To make space for intimate talk in these sprawling open spaces, architects devised a novel (some might say novelty) solution: the conversation pit.

The Finnish-American architect Eero Saarinen, along with industrial designer Char...