Investigator Botax and Captain Garm are alien researchers who are trying to understand humans and bisexual reproduction. Unfortunately, they're hindered by getting their ideas from Science Fiction stories. Botax attempts to invoke several tropes in their attempt to make the male/female pair "cooperate". It goes very poorly.
"What Is This Thing Called Love?" has been republished several times; Dodici Volte Domani (1964), Great Science Fiction From Amazing (1965), Science Fiction Oddities (1966), Urania (issue #455, February 1967), Nightfall and Other Stories (1969), Liebe 2002 (1971), Sex in the 21st Century (1979), Le Livre d'Or de la Science Fiction: Isaac Asimov (1980), Flying Saucers (1982), Amazing Stories: 60 Years of the Best Science Fiction (1985), The Complete Stories, Volume 1 (1990), Alef, #22 (November 1990), Isaac Asimov Presents: The Great Science Fiction Stories, Volume 23 (1961) (1991), The Wizards of Odd: Comic Tales of Fantasy (1996), UFOs: The Greatest Stories (1996), and Girls for the Slime God (1997).
"What Is This Thing Called Love?" contains examples of:
- Alien Abduction: The alien researcher kidnaps two people from a train station to demonstrate how humans engage in reproduction.
- Aliens Made Them Do It: The story is a parody of this trope - the aliens would like to make them do it, but are completely clueless about how to.
- Bioluminescence is Cool: The alien protagonists communicate using light, causing difficulty in understanding human biology including speech (which one of them describes as "a sort of complicated coughing").
- Bizarre Alien Reproduction: The alien protagonists are an asexually reproducing species. One alien researcher is trying to convince his boss that Earth animals have bisexual reproduction, although neither one really understand the difference between mating and courtship, and the subjects they kidnap are too embarrassed to explain anything.
- The Cassandra: Botax is unable to convince Garm that humans reproduce sexually.
- Deconstruction: The story was written as a counterpoint to a Playboy article "Girls of the Slime God" by William Knowles, which presented a tongue-in-cheek picture of science fiction as lurid tales about aliens and sex. Asimov took a (somewhat) more serious approach to the question of how aliens might take an interest in human sexuality.
- Fantastic Anthropologist: The alien protagonists are abducting humans in order to better understand us.
- Genre Savvy: Investigator Botax, an alien anthropologist, has studied our literature in an attempt to understand humanity. During their demonstration to Captain Garm, they read excerpts from several erotic stories, especially "Recreationlad".
- Hooked Up Afterwards: Once the aliens have returned them to Earth, the two abducted humans start discussing their weird experience, and one thing leads to another...
- Humans Are Special: One alien researcher is trying to convince his boss that Earth animals have bisexual reproduction and this is a problem due to the way that recombination hastens evolutionary biology compared to asexual reproduction.
- Humans Through Alien Eyes: Our primary viewpoint character is slimy bug-eyed monsters, part of an advanced scouting mission. They find humans strange for many reasons, especially our sexual dimorphism and bisexual reproduction. They abduct a pair of humans to demonstrate these qualities to their superior, who finds their claims too disgusting to be believable.
- Learnt English from Watching Television: The alien researcher has spent months studying humanity from a spy cell on Earth. It learned English (and about our sexual lives) from capturing public broadcasts. They don't normally use sound to communicate, so English is difficult to mimic, but it is reasonably close.
- Literary Allusion Title: The original title, "Playboy and the Slime God", refers to Playboy magazine and one of their articles, "Girls for the Slime God". It presents a parody of what one would expect from erotic science-fiction.
- Sexy Discretion Shot: Parodied when an alien researcher, who has been studying human literature, is frustrated by the fact that stories always fade out after The Big Damn Kiss when describing human procreation. The researcher is aware there is more, it's the fact that there is never more described that frustrates them. It is also misled by the unrealistically described... hmmm... courting rituals.
- Shout-Out: One of the more popular periodicals that Botax uses to research human mating rituals is called "Recreationlad".
- Starfish Language: The alien protagonists communicate by changing their color. A Translation Convention is in effect for the audience, but to communicate with the human test subjects, one alien demonstrates their ability to make "modulated sound waves".
- What Is This Thing You Call "Love"?: Our alien protagonists reproduce asexually. The researcher stationed on Earth has abducted two humans to demonstrate sexual reproduction and human mating rituals to their boss. They are focused on trying to demonstrate lust and sex rather than "love".