《幻愛》與黑羊

以下有些微劇透。容我儘量以不打擾觀賞為前提下，略談《幻愛》中一個隱藏的符號。

片中有一點頗教人在意，就是阿樂反覆夢到自己是隻黑羊，受困墓園綠茵裏，輔導員再解畫一番，未免生搬硬套，不肖香港風土人情，倒不及濕地中一條基圍蝦、蠔排底一條金豉魚來得地道呢。

既有生搬硬套之跡，我猜黑羊必有來歷。好奇之下，開始明查暗訪。原來黑羊乃歐洲俚語，一般字典都有收錄，泛指在族群中最受薄待的個體。有說此喻源於黑羊毛不易漂染，故比白羊毛價賤。亦有說十六世紀時，人視黑羊為魔鬼印記。（參考 Christine Ammer (1997). The American Heritage Dictionary of Idioms：「This metaphor is based on the idea that black sheep were less valuable than white ones because it was more difficult to dye their wool different colors. Also, in the 16th century, their color was considered the devil's mark. By the 18th century the term was widely used as it is today, for the odd member of a group.」）而黑羊作貶稱的最早的明文記載，見於麥克林（Charles Macklin）劇作《The man and the world》：「O, ye villain! you - you - you are a black sheep; and I'll mark you.」

及後，心理學家憑此語起名，提出黑羊效應一說。按美國心理學會網上詞典所載，黑羊效應指比起族群外，人傾向對族群內不受歡迎的人更苛刻。（「the tendency to evaluate a disreputable or disliked person more negatively when that person is a member of one’s own group rather than of some other group. Although an apparent contradiction of ingroup bias, the black sheep effect is explained by social identity theory: People respond negatively to those who act in ways that threaten their group’s identity, particularly when they affiliate strongly with their group」）確立此說之論文發表於一九八八年，題為〈The 'Black Sheep Effect': Extremity of judgments towards ingroup members as a function of group identification〉，其中持見修正了社會認同論。按社會認同論，人傾向圍爐取暖，偏愛同路人，藉此也維護了自己。故而即便有同樣不受歡迎的人，比起族群內，我理應會更薄待族群外那一個。例如同樣劣食，黃絲理應會給藍店更低評分。論文卻提出異見，以自己圈內的黑羊會比圈外的黑羊更討厭。不過黑羊效應並未推翻社會認同論，反倒可說明人為了保存自身利益，鄙棄害群之馬的行為。（「The black sheep hypothesis is thus in accordance with Social Identity Theory: The under-evaluation of dislikeable ingroup members may be an acceptable psychological strategy for preserving the group’s overall positivity. Therefore, the black sheep effect should be considered a ‘sophisticated’ form of ingroup favouritism.」）這大概令人聯想到比起外敵，人往往會為更痛恨內奸而頻頻捉鬼。

另外，精神醫學界似乎流傳掛名為黑羊的人格分析，奇奇怪怪，觀點可疑，甚至有人將之與黑羊效應混為一談，於此就不多作介紹。有趣的是美國心理學會前主席利伯曼（Jeffrey Lieberman）有本書叫《Shrinks: The Untold Story of Psychiatry》，詳述精神醫學史，其中他自嘲精神醫學為醫學家庭的黑羊（「the black sheep of the medical family」）。希望他朝再另文詳談。