The narrator of the story, Annie is Ben's lover and by-stander in his pre-evolution. As Ben comments in the narrative, he and Annie "think far too much." She mostly concentrates on other things and lacks imagination. For example, when Annie and Ben have sex for the first time, she leaves the lights on and "concentrated really hard on letting go." Even though Annie does "over-think," she still deeply cares for Ben. This is evidenced when she finds Ben as an ape and has the heart to get to know him.
Ben is Annie’s lover and the man who goes through reverse evolution. During the narrative Ben is morbid, which is probably because Ben, like Annie thinks too much; he realizes this and questions it. As Ben says “We’re all getting too smart. Our brains are just getting bigger and bigger, and the world dries up and dies when there’s too much thought and not enough heart.” A day before Ben goes through his reverse evolution track; he realizes that “there is no space for anything but dreaming.” That maybe people should stop thinking all the time and for a while, follow their heart, and dream. It could be assumed, that Ben tried to stop thinking, but for him it was too much. In the end, it seems the only way Ben can finally stop thinking was to regress into primitive forms, “to stop being human.”