Katherine MacLean (1925– ) is an underrated US writer of science fiction specializing in short stories, most of which, including her first, “Defense Mechanism” (1949), appeared in Astounding Science Fiction. MacLean began to apply so-called soft science such as sociology to science fiction long before the rise of the Humanists in the 1980s. MacLean had a wide range of interests outside of writing that influenced her fiction. MacLean’s education background included a BA from Barnard with postgraduate work in psychology. Although her work was unique and sophisticated, MacLean published little in the 1960s and her work was largely invisible to the New Wave writers who might have found it of interest.
MacLean’s explorations in fiction often harness the hard sciences as well, to create a generally optimistic tone in stories that deal with a wide range of technological matters. Although she expressed feminist themes in some stories, MacLean did not restrict herself to those themes or protagonists, and did not generally use a male pseudonym. A number of her stories were assembled in The Diploids and Other Flights of Fancy (1962) and The Trouble with You Earth People (1980).
Many of MacLean’s early stories have been anthologized. Perhaps the best-known are “Pictures Don’t Lie” (Galaxy, August 1951), which tells of the arrival of an alien spaceship that seems normal according to advance radio signals but turns out to be little more than microscopic; “Unhuman Sacrifice” (Astounding Science Fiction, November 1958), an important piece of anthropological SF in which a visiting exploration/contact team on another planet misreads a painful initiation ceremony as needless when its purpose is to prevent a damaging biological change; and the story reprinted here, “The Snowball Effect.”
“The Snowball Effect” (Galaxy, 1952) is unusual in subject matter. The story deals with academia in a sociology setting and shows how such research can make a huge impact in our future. In showcasing an insufficiently rigorous and absurdly failed experiment, the story also examines the ethics of experimenting on people without their knowledge (long before this issue was acknowledged). MacLean’s work as a college lecturer may also have influenced this story.