当我们听到有趣的笑话时定会忍俊不禁。然而，这并不是最常见的“发笑因素”，最能引人开怀大笑的究竟是什么呢？答案其实很简单：与人共处。研究显示，和他人在一起时发笑的频率是独处时的三十倍，而且人类并不是唯一能被逗乐的物种。What makes you laugh the most?While rib-ticklingjokes and hilariousvideos certainly do make us giggle， most of the time we laugh because of something much simpler: being with other people.So much so that we are 30 times more likely to laugh when we're with others， according to a study by neuroscientistRobert Provine from the University of Maryland. 'When you're alone， laughter basically disappears，' he told Smithsonian Magazine.So， what is it about other people that makes us split our sides? The answer lies deep within our brains， and in how we form communities.Laughter is a social emotion that we use to 'make and maintain social bonds，' says Professor Sophie Smith from University College London in an article for the BBC. It reassures people that situations are non-threatening. Those who laugh frequently are also often more popular. Even in a normal conversation we laugh seven times every 10 minutes， she says. Professor Smith also explains that laughter is very different to speech. It is non-verbal: thewheezingand snortingsounds are produced by air being pushed out quickly at high pressure， without involving the teeth or lips. These sounds are the kind we make when in a state of heightenedemotion.In this respect， laughter sounds more like an animal call than human language. This theory is backed upby tests which show the part of the brain responsible for laughter is not theneocortexused in language， but an 'older' area we share with mammals.Indeed， chimpanzees， gorillas and even rats all enjoy a good chortle， especially when being tickled. Just be careful when you tickle a gorilla， or you might end up laughing on the other side of your face… (Did you laugh at that gag? Or did it just make you groan?)词汇表rib-tickling 令人捧腹大笑的hilarious 滑稽的giggle 咯咯地笑neuroscientist 神经科学家split your sides 笑裂腰身，笑破肚皮social bond 社会关系non-threatening 不具威胁性的non-verbal 非语言的wheeze 发出喘息声snort 用鼻子哼heightened emotion 高度激动的情绪back up 证实，有证据支持neocortex 大脑新皮层chortle 哈哈大笑laugh on the other side of your face （口语比喻）转喜为忧、乐极生悲gag 玩笑、俏皮话groan 哼了一声测验与练习1. 阅读课文并回答问题。1. Why do we laugh so much when we're with others?2. How is laughing unlike speaking?3. If I tell a bad joke does it make you split your sides or groan?4. How do you make a rat laugh?5. True or false? The part of the brain responsible for speaking is newer than the part used for laughing.