Why do we laugh and get amusement from so many different things，from puns (双关语) to pratfalls? Why are some things funny to some people and not to others? How is that while a successful joke can cause pleasure，a sick one can cause serious harm?
Over the centuries，various scholars have attempted to produce a universally agreed-upon theory of humor．Plato and Aristotle introduced the superiority(优越感) theory，the idea that people laugh at the misfortune of others．Their theory seems to explain teasing，but it doesn’t work well for knock-knock jokes．Sigmund Freud argued for his relief theory，the concept that humor is a way for people to release psychological tension and reveal their inner fears and desires．His theory works well for dirty jokes，less well for most puns．
The majority of humor expels today agree with the incongruity theory，the idea that humor arises when there’s a gap between what people expect to happen and what actually happens．Incongruity has a lot going for it — jokes with unexpected funny lines，for example，fit well．But scientists have found that in comedy，unexpectedness is overvalued．
With the goal of developing a new，more satisfactory explanation，I produced “the gentle violation(违背)theory”，the idea that humor arises when something seems wrong or threatening，but is actually OK or safe．A dirty joke，for example，trades on moral or social violations，but it’s only going to get a laugh if the person listening is open enough to consider the subject OK to talk about．Similarly，puns can be seen as linguistic violations that still make grammatical sense．
And while most humor theories have struggled to account for tickling (挠痒痒)，or just avoided the phenomenon altogether，my theory accounts for even this kind of laughter．Tickling involves violating someone’s physical space in a gentle way．People can’t tickle themselves — because it isn’t a violation．
What is the author’s attitude towards Plato and Aristotle’s theory?

A．Critical．

B．Approving

C．uncaring

D．Unclear

According to Sigmund Freud’s theory，we can infer that __________ .

A．people will laugh when they see others suffer

B．telling dirty jokes is a relief of one’s nervous feelings ’

C．unexpectedness can explain how humor works

D．tickling doesn’t involve psychological tension

According to the author，why are some things funny to some people but not to others?

A．Because the sense of humor varies greatly from person to person．

B．Because people have different expectations for the same thing．

C．Because some people lack the sense of safety deep in their heart．

D．Because people’s understanding of violation is different．

What is the author’s main purpose of writing this passage?

A．To draw people’s attention to the research of humor．

B．To criticize people’s misconceptions about humor．

C．To explain what exactly causes people to laugh．

D．To prove the sense of humor can be developed．