Why do not

It is more common in writing than in speaking. When you are sure that you understand the lesson, you can continue with the exercises. Tel Email elcreg uvic.

Toggle navigation Menu. This shows that it is not necessary for Alex to call his mother. For example: In Canada, children do not have to go to school on Saturdays, but many adults have to work. Maggie doesn't have to study tonight because she studied all day.

Common Question : Does Maggie have to study tonight? Question : Did we have to read Chapter 5 last night? It's illegal! Out of twenty-five pairs of notes, they correctly identified the real one twenty-four times.

Others discovered that they were hopeless. They identified the real note in only ten instances. As is often the case with psychological studies, the whole setup was a put-on.

In the second phase of the study, the deception was revealed. The students were told that the real point of the experiment was to gauge their responses to thinking they were right or wrong.

This, it turned out, was also a deception. Finally, the students were asked to estimate how many suicide notes they had actually categorized correctly, and how many they thought an average student would get right. At this point, something curious happened. A few years later, a new set of Stanford students was recruited for a related study.

The students were handed packets of information about a pair of firefighters, Frank K. George had a small son and played golf. According to one version of the packet, Frank was a successful firefighter who, on the test, almost always went with the safest option. The students were then asked to describe their own beliefs. What sort of attitude toward risk did they think a successful firefighter would have?

The Stanford studies became famous. Thousands of subsequent experiments have confirmed and elaborated on this finding. Rarely has this insight seemed more relevant than it does right now. Still, an essential puzzle remains: How did we come to be this way? Mercier, who works at a French research institute in Lyon, and Sperber, now based at the Central European University, in Budapest, point out that reason is an evolved trait, like bipedalism or three-color vision.

It emerged on the savannas of Africa, and has to be understood in that context. For any individual, freeloading is always the best course of action. Reason developed not to enable us to solve abstract, logical problems or even to help us draw conclusions from unfamiliar data; rather, it developed to resolve the problems posed by living in collaborative groups.

One of the most famous of these was conducted, again, at Stanford. For this experiment, researchers rounded up a group of students who had opposing opinions about capital punishment. Half the students were in favor of it and thought that it deterred crime; the other half were against it and thought that it had no effect on crime. The students were asked to respond to two studies. One provided data in support of the deterrence argument, and the other provided data that called it into question.

Both studies—you guessed it—were made up, and had been designed to present what were, objectively speaking, equally compelling statistics.

At the end of the experiment, the students were asked once again about their views. Imagine, Mercier and Sperber suggest, a mouse that thinks the way we do. A recent experiment performed by Mercier and some European colleagues neatly demonstrates this asymmetry.

Both don't and doesn't are contractions. Don't is a contraction of do not , while doesn't is a contraction of does not, and they both act as auxiliary verbs.

In English, don't is used when speaking in the first and second person plural and singular and the third person plural "I," "you," "we," and "they". It can be used to make a negative statement: I don't like seafood.

You don't want to do that. We don't want to go home yet. They don't have to pay now. It can also be used when asking a question: You want to buy one, don't you? Don't they want to go? Doesn't , on the other hand, is used when speaking in the third person singular only "he," "she," and "it". Like don't, doesn't is used to make negative statements: He doesn't like me. She doesn't want to leave now. It doesn't look like he'll be able to make it.

And it is also used when asking a question: Doesn't she like the play? It looks like rain, doesn't it?