en grupp människor låst i ett hus och observeras som faktiskt är martians

Det är Brian W. Aldiss Outside . Kort sammanfattning här:

Four men and two women live in a habitat which feeds them, allows them to play piano, and live day-to-day amid various domestic duties and pastimes. Harley, after years of doing the same things, feels an unease that he suspects his companions may not share. One night, when the command to sleep presses his brain, he decides to stay awake.

Harley discovers a whole world outside his habitat. An inexplicable sad rage comes over him at this injustice as he encounters a man in a suit and several uniformed men. The suited man explains that this war with the Nititians required them to isolate the Nititian spies from prying state secrets out of agents. Instead, the Nititians... play card games and the piano and clean the habitat? This leads to Earthlings learning Nititian secrets to defeat the menace.

En liknande historia i Isaac Asimovs repertoar är Den nakna solen . Från wikibeskrivningen:

The book focuses on the unusual traditions and culture of Solarian society: the planet has a rigidly controlled population of twenty thousand, and robots outnumber humans ten thousand to one, whereas people are strictly taught from birth to despise personal contact, and live on huge estates, either alone or with their spouse only. Communication is done via holographic telepresence (called viewing, as opposed to in-person seeing). Baley insists on face to face conversations, traveling in a closed vehicle because of his own agoraphobia, from his life in the enclosed cities of Earth.