Why Do Babies Laugh out Loud?
By Tom Stafford 莘绮 选 王维 注
What makes babies laugh? It sounds like one of the most fun questions a researcher could investigate1, but there’s a serious scientific reason why Caspar Addyman wants to find out.
He’s not the first to ask this question. Darwin studied laughter in his infant son, and Freud formed a theory that our tendency to laugh originates in a sense of superiority.2 So we take pleasure at seeing another’s suffering—slapstick style pratfalls and accidents being good examples—because it isn’t us.3
The great psychologist of human development, Jean Piaget, thought that babies’ laughter could be used to see into their minds.4 If you laugh, you must “get the joke” to some degree—a good joke is balanced in between being completely unexpected and confusing and being predictable and boring.5 Studying when babies laugh might therefore be a great way of gaining insight into how they understand the world, he reasoned.6 But although he proposed7 this in the 1940s, this idea remains to be properly tested. Despite the fact that some very famous investigators have studied the topic, it has been neglected by modern psychology.
Addyman, of Birkbeck, University of London, is out to change that. He believes we can use laughter to get at exactly how infants understand the world. ’He’s completed the world’s largest and most comprehensive survey of what makes babies laugh, presenting his initial results at the International Conference on Infant Studies, Berlin, last year.8 Via his website he surveyed more than 1,000 parents from around the world, asking them questions about when, where and why their babies laugh.
The results are—like the research topic—heart-warming. A baby’s first smile comes at about six weeks, their first laugh at about three and a half months (although some took three times as long to laugh, so don’t worry if your baby hasn’t cracked its first cackle just yet).9 Peekaboo is a sure-fire favourite for making babies laugh, but tickling is the single most reported reason that babies laugh.10
Importantly, from the very first chuckle11, the survey responses show that babies are laughing with other people, and at what they do. The mere physical sensation of something being ticklish isn’t enough.12 Nor is it enough to see something disappear or appear suddenly. It’s only funny when an adult makes these things happen for the baby. This shows that way before babies walk, or talk, they—and their laughter—are social. If you tickle a baby they apparently laugh because you are tickling them, not just because they are being tickled.
What’s more, babies don’t tend to laugh at people falling over. They are far more likely to laugh when they fall over, rather than someone else, or when other people are happy, rather than when they are sad or unpleasantly surprised. From these results, Freud’s theory (which, in any case, was developed based on clinical interviews with adults, rather than any rigorous formal study of actual children)—looks dead wrong.13
Although parents report that boy babies laugh slightly more than girl babies, both genders find mummy and daddy equally funny.
Addyman continues to collect data, and hopes that as the results become clearer he’ll be able to use his analysis to show how laughter tracks babies’ developing understanding of the world—how surprise gives way to anticipation14, for example, as their ability to remember objects comes online.
Despite the scientific potential, baby laughter is, as a research topic, “strangely neglected”, according to Addyman. Part of the reason is the difficulty of making babies laugh reliably in the lab, although he plans to tackle15 this in the next phase of the project. But partly the topic has been neglected, he says, because it isn’t viewed as a subject for “proper” science to look into. This is a prejudice Addyman hopes to overturn16—for him, the study of laughter is certainly no joke.
1. investigate: 调查，研究。
2. infant: 婴儿，幼儿；Freud: 弗洛伊德，奥地利精神病医师、心理学家；originate: 引发，起源于；superiority: 优越性。
3. 我们会以他人的痛苦为乐——比如看到别人滑稽地跌坐在地或是发生意外——因为痛苦的人不是我们。slapstick: 恶作剧，闹剧；pratfall: 屁股着地的坐跌，可笑的失误。
4. psychologist: 心理学家；Jean Piaget: 让·皮亚杰，法籍瑞士人，近代有名的儿童心理学家。
6. gain insight into: 对……深入了解，熟悉；reason: 推断。
7. propose: 提出（想法、理论等）。
8. comprehensive: 综合的，全方位的；initial: 最初的。
9. 婴儿的第一次微笑大约出现在出生后的六周，他们的第一次大笑大约出现在出生后的三个半月（有些婴儿要花三倍的时间才会大笑，所以如果你的孩子还没有笑出声来，你也不用担心）。crack: 绽露（笑容）；cackle: 咯咯笑。
10. peekaboo: 躲猫猫（一种把脸一隐一现来逗小孩的游戏）；sure-fire: 一定的，绝对的；tickle: 挠痒痒。
11. chuckle: 咯咯笑，轻声笑。
12. mere: 极小的；sensation: 感觉；ticklish: 痒的。
13. clinical: 临床的；rigorous: 严谨的，严格的；dead wrong: 大错特错。
14. anticipation: 期望，预料。
15. tackle: 处理。
16. prejudice: 偏见；overturn: 推翻，倾覆。