The taboo against incest runs deep, as the social psychologist Jonathan Haidt demonstrated when he told experimental subjects about Julie and Mark, adult siblings who take a holiday together and decide to have sex, just to see what it would be like. In the story, Julie is already on the Pill, but Mark uses a condom, just to be safe.
人们对于乱伦的禁忌根深蒂固，社会心理学家乔纳森•海特面对受试者讲述朱莉和马克这对成年兄妹一起度假，并决定发生性关系，只为看看它是什么样子的。故事中的朱莉已经在服用避孕药，但马克为了安全起见仍旧使用了避孕套。两人都很享受这种体验，但决定不再这样做。这次秘密经历增加了他们的亲密度。