Abstract: The internet has significantly changed teenager’s media behaviors today, especially the Media Multitasking Behavior. Media Multitasking can be defined as using multiple media tools or engaging in multiple media tasks at the same time. It does have same impacts on teenager’s cognitive development, academic achievement, social interaction, problem behavior, and so on. This paper will attempt to describe this popular media phenomenon in teenagers. Firstly, the definition of Media Multitasking Behavior has been introduced with the summarization of its relative theoretical basis .There have three theories which can be employed to explain media multitasking: 1, Use & Gratification Theory ;2, Self-Determination Theory, 3,The Limited Capacity Theory. Then the paper introduce three simple but useful measurements of Media Multitasking, one is based on numbers of media tools(MUQ) and the other is based on media time. The last but not least is SPD, which includes the MUQ. To explore which factors could strengthen teenager’s media multitasking behavior, this paper firstly generalizes the influence factors of Media Multitasking from previous research and concludes three factors : the media tools or media behavior itself, the unique of teenagers groups which include physical features and personality, the media environment. Since media impacts teenagers a lot that there have numerous researches to support .What’s the unique influences of Media Multitasking Behavior? Through a comprehensive review of previous research, three aspects have been brought up:1, the cognition results and academic performance of teenagers, in this aspect, there have two different opinions which one think media multitasking is impaired teenager’s cognitive process and academic performance and the other insist there have same different influences; 2, the social interactions of teenagers, in this aspect, many researchers think media is associated with negative social interaction, and so does media multitasking, although teenagers always choose one social media task at least, what we cannot deny is that social media behavior in media multitasking does bring emotional satisfaction to teenagers; 3 some researches have found high media multitasking teenagers will have more problem behaviors, maybe these teenagers have lower information threshold to media content than their companion, obviously, they are more suspect to negative or violent information. The conclusion points out that it is necessary to strengthen the research on the impact of emerging media such as smart-phone to the media multitasking, gender difference in media multitasking, ecology measurement of media multitasking and the positive influence of media multitasking in the future. Reasons are as follows，Firstly, since smart-phone、i-pad have become more and more popular, teenagers can use their media everywhere and anytime, which can accelerate media multitasking, and maybe have same complicated influences. Second, although man is influenced deeply in media than woman, it seems the influences is turned around in media multitasking behaviors. This is worth to notice because researches have point out women are more involved in media multitasking behaviors. Third, how to measure media multitasking behaviors more ecological and authentic is still a problem to future research. At last but not least, as an irresistible trend , media multitasking behaviors need more positive research to leverage its power.

Key words: Media Multitasking Behaviors, teenager, psychology development

摘要： 计算机时代的到来带来了青少年媒体使用行为的变化，其中媒体多任务现象尤为显著。为全面了解在青少年群体中日渐普及的媒体多任务行为，本文首先介绍该现象的概念界定，其次概括研究中的理论基础和测量方式，并总结了青少年媒体多任务的影响因素和影响后果。未来应加强对智能手机等新兴媒体对媒体多任务行为的影响、媒体多任务行为的性别差异、媒体多任务行为的生态化测量以及媒体多任务行为积极影响的研究。

关键词: 媒体多任务行为, 青少年, 心理发展