Persuasion is the art of convincing someone to agree with you. According to the ancient Greeks，there are three basic tools of persuasion：ethos，pathos，and logos.

Ethos is a speakers way of convincing the audience that she is trustworthy，honest and reliable. One common way a speaker can develop ethos is by explaining how much experience or education she has in the field. After all，you’re more likely to listen to advice about how to take care of your teeth from a dentist than a fireman. A speaker can also create ethos by convincing the audience that she is a good person. If an audience cannot trust you，you will not be able to persuade them.

Pathos is a speaker’s way of connecting with an audience’s emotions. For example，a politician who is trying to convince an audience to vote for him might say that he alone can save the country from a terrible war. These words are intended to fill the audience with fear，thus making them support him. Similarly，an animal charity might show an audience pictures of injured dogs and cats，to make the viewers feel pity. If the audience feels bad for the animals，they will be more likely to donate money.

Logos is the use of facts，statistics，or other evidence to support your argument. An audience will be more likely to believe you if you have convincing data to back up your claims. Presenting this evidence is much more persuasive than simply saying "believe me".

Although ethos，pathos，and logos all have their strengths，they are often most effective when used together. Indeed，most speakers use a combination of ethos，pathos，and logos to persuade their audiences. So，the next time you listen to a speech，watch a commercial，or listen to a friend try to convince you to lend him some money，be on the lookout for these ancient Greek tools of persuasion.

The human eye can perceive about 1 million colors, but languages have far fewer words to describe those colors. Languages spoken in industrialized nations such as the United States, for example, tend to have about a dozen basic color terms, while languages spoken by populations in remote areas often have fewer. However, the way that a language divides up color space can be influenced by contact with other languages, according to a new study.

Among members of the Tsimane society, who live in a remote part of the Bolivian Amazon rainforest, the researchers found that those who had learned Spanish as a second language began to classify colors into more words, making color distinctions that are not commonly used by Tsimane who are monolingual (单语的).

In the most striking finding, Tsimane who were bilingual (会双语的) began using two different words to describe blue and green, which monolingual Tsimane speakers do not typically do. The researchers also found that the bilingual Tsimane became more precise in describing colors such as yellow and red, which monolingual speakers tend to use to include many shades (色度) beyond what a Spanish or English speaker would include.

Working with monolingual and bilingual members of the Tsimane, the researchers asked people to perform two different tasks. For the bilingual population, they asked them to do the tasks twice, once in Tsimane and once in Spanish.

In the first task, the researchers showed the subjects 84 chips (块) of different colors, one by one, and asked them what word they would use to describe the color. In the second task, the subjects were shown the entire set of chips and asked to group the chips by color words.

The researchers found that when performing this task in Spanish, the bilingual Tsimane classified colors into the traditional color words of the Spanish language. Additionally, the bilingual speakers were much more precise about naming colors when they performed the task in their native language.

“The bilingual speakers learned a different way to divide up the color space,” says Edward Gibson, the senior author of the study. “It’s a great example of one of the main benefits of learning a second language. You open a different world and understand different concepts that you import to your native language.”