There are also some other studies on PSAs。 Advertising as Public Service by Joseph Herbert Appel illustrates that the language of PSAs should be forceful, accurate, touching and attractive。 Effects of Persuasive Appeals in Public Service Advertising written by Lynn, Jerry R indicates that source-attribute is the least effective method of advertising, while emotional appeal is the most effective method of advertising。 (Zhang 266)

 When reviewing Chinese and American scholars’ researches on public service advertisements, it can be easily found that most of the scholars concentrated on analyzing the specific content of public service advertisements, exploring the performance techniques of public service advertisements, studying the spread effect of public service advertisements and examining the social role of public service advertisements。 In other words, scholars studied PSAs from linguistic and semiotic, functional, and value perspective, few researches are carried out from the perspective of high and low context theory。 The thesis thus compares the differences of Chinese and American PSAs concerning non-smoking, and explores the reasons for the differences from the perspective of high and low context theory。

2。2 High and low context theory文献综述

     American anthropologist Edward Hall pointed out the importance of culture in people’s social life。 He said: “Culture is the environment of human life, all aspects of human life are influenced by culture, and change with the change of culture, or, culture determines the existence of people, including the way of self-expression and emotional expression, the way of thinking, the way of action and the way of solving the problem, etc。 These cultural aspects which are very obvious in the general case but rarely studied by people, affect people’s behavior in the most profound and subtle way。” (Hall 78) Hall also proposed an effective way to study cultural differences from the perspective of communication and perception。

     In his book Beyond Culture in 1976, Hall put forward the notion of high and low context, presents culture is contextual for the first time and pides culture into high context culture and low context culture。 In his view, the so-called high-context message exchanges or high-context means that most of the information is stored in the physical environment, or internalized in the person, while very little information is in the coded, explicit, and transmitted part of the message。 Low contextual communication is adverse to the high contextual communication, a lot of information is edited into the explicit code。 From this we can see that the semantic carrier in high context culture is not mainly linguistic, but non-linguistic and contextual, while low context culture is mainly expressed by language。 

     “Although no culture exists exclusively at one end of the scale, some are low while others are high。 American culture, while not on the bottom, is toward the lower end of the scale。。。 Chinese people tend to be high-context communicators as compared to people from western countries。。。” (Hall 91) In other words, America is a typical case of low-context culture while China tends to have apparent high-context culture。