Imperfect Perception
Is perception flawless? Hardly. For one thing, it is influenced by our desires, interests, and expectations: “From the outset perception is selective and tends to simplify the world around us. Memory continues and hastens the process.”2 For another, even within its limited focus, perception is often flawed. A college student who is positive that the textbook contains a certain statement answers an exam question with perfect confidence. Yet when the student gets the corrected test back and finds the question marked wrong, then hurriedly flips open the book and examines the passage again, he or she may find it says something else entirely.
Moviegoers in the 1930s and 1940s were thrilled as Tarzan uttered his famous yell and swung through the treetops to catch the villain. Tell them that Tarzan never made that yell and they’ll say, “False, we heard it with our own ears.” And yet it’s not false. According to one of the men who first played the “role of Tarzan, Buster Crabbe,” that yell was dubbed into the films in the studio. It was a blend of three voices—a soprano’s, a baritone’s, and a hog caller’s.
At least a dozen times every weekend from September to January, the imperfection of human observation is underlined by that marvel of technology, the instant replay. Is there a football fan anywhere who doesn’t occasionally scream, “Bad call!” only to be proved wrong a moment later? We can be sure enough to bet a week’s wages that the pass receiver’s feet came down inbounds or that the running back’s knee hit the ground before the ball came loose. And then the replay shows us how erroneous our initial perception was.
The vagaries of perception have long been noted by those who deal with human testimony—notably, trial lawyers, police officers, and psychologists. It is well established that a number of factors can make us see and hear inaccurately. Darkness, cloudy conditions, or distance from what we are witnessing may obscure our vision. We may be distracted at a crucial moment. If we are tired or in the grip of powerful emotions such as fear or anger, our normal perceptiveness may be significantly diminished.
Also, perception may be intermingled with interpretation—the expectation that an event will unfold in a certain way may color our perception of the way the event actually unfolds. Loyalty and affection toward the people or things involved may distort our vision as well. If someone we dislike speaks in a loud voice and is animated, we may regard that person as showing off to get attention. But if a friend behaves in the same way, we may regard him or her as vivacious and extroverted.
- Gordon W. Allport and Leo Postman, The Psychology of Rumor (New York: Russell & Russell, 1965 [1947]), p. 100.
不完美的感知
感知是完美无缺的吗?几乎没有。首先，它受到我们的欲望、兴趣和期望的影响:“从一开始，感知是有选择性的，它会简化我们周围的世界。记忆会继续并加速这个过程。”（2）另一方面，即使在有限的关注范围内，人们的看法也常常是有缺陷的。一个大学生如果对教材中包含的某一陈述持肯定态度，那么他会非常自信地回答与之相关的考题。然而，当学生拿回批改过的试卷，发现那个被标注为错误的考题，然后匆忙翻开书本，再次检查教材上那篇文章时，他或她可能会发现教材完全说了另一件事。
20世纪30年代和40年代，当泰山发出他那著名的叫声，并且在树梢上荡来荡去抓住那个恶棍时，电影观众们都激动不已。如果告诉他们泰山从来没有发出那样的叫声，他们会说:“不对，这是我们亲耳听到的。”但这并不是错的。据第一个扮演“泰山巴斯特·克拉布”角色的人说，这种被电影制片厂配音进了电影里的叫声是三种声音的混合体——女高音、男中音和猪叫声。
从9月到1月，每个周末至少有十几次，技术的奇迹：即时回放——突显了人类观察能力的不完美。世界上有哪个橄榄球球迷不会偶尔尖叫一声“糟糕的判罚!”然后一会儿就被证明是错的?我们可以用一个星期的工资打赌:接球手的脚落在了界内，或者跑垒后卫的膝盖在球松动之前撞到了地上。然后回放告诉我们，我们最初的感知是多么的错误。
那些处理人类证词的人，尤其是审判律师、警察和心理学家，早就注意到了知觉的奇特。许多因素能使我们看到的和听到的不准确，这是确定无疑的。黑暗，多云的环境，或我们目击的距离，都可能会模糊我们的视线。我们可能在关键时刻分心。如果我们感到疲倦，或者处于恐惧或愤怒等强烈情绪的控制下，我们的正常感知能力可能会显著减弱。
此外，感知可能与理解混杂在一起——对事件将以某种方式展开的预期可能会影响我们对事件实际展开方式的感知。对所涉及的人或事的忠心和情感也会扭曲我们的视野。如果我们不喜欢的人说话声音很大，而且很活跃，我们可能会认为那个人是在炫耀以引起注意。但是如果一个朋友也这样做，我们可能会认为他或她是活泼外向的。
2.《谣言心理学》(纽约:罗素与罗素出版社，1965[1947])，第100页。
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