Earth sends a few (4?) couples on a short near-light speed round trip to see how they are affected, not telling them some important facts. They evolve very rapidly, first dropping all social mores, then increasing in intelligence/power well beyond Earth people, arriving home angry(?). Was included in a collection with a short by John Varley (Persistence of Vision).

  • 1
    Are you 100% sure it appeared in a collection with John Varley's "Persistence of Vision"? – user14111 Jan 19 '15 at 7:38
  • 4
    Because your description reminds me of Pohl's "The Gold at Starbow's End" which has been the answer to previous questions on this site, but the ISFDB does not seem to show any collections that contain both "Starbow" and "Persistence". – user14111 Jan 19 '15 at 7:43
  • 1
    Oops, wrong link. Here is the the ISFDB page which lists the collections where Pohl's novella "The Gold at Starbow's End" has appeared. – user14111 Jan 19 '15 at 8:27
  • 1
    Thank you, I think that's it! I guess my memory is creating a collection that doesn't exist, but it was a long time ago. I probably read them close together. – Rob Jan 19 '15 at 14:41
  • Great! If "The Gold at Starbow's End" turns out not to be the right story, please post another question, and (if possible) try to provide more details. – user14111 Jan 19 '15 at 17:54