The people who multitask the most are the ones who are worst at it. That's the surprising conclusion of researchers at Stanford University, who found multitaskers are more easily distracted and less able to ignore irrelevant information than people who do less multitasking.

"The huge finding is, the more media people use the worse they are at using any media. We were totally shocked," Clifford Nass, a professor at Stanford's communications department, said in a telephone interview.

The researchers studied 262 college undergraduates, dividing them into high and low multitasking groups and comparing such things as memory, ability to switch from one task to another and being able to focus on a task. Their findings are reported in Tuesday's edition of Proceedings of the National Academy of Sciences.

When it came to such essential abilities, people who did a lot of multitasking didn't score as well as others, Nass said.

Still to be answered is why the folks who are worst at multitasking are the ones doing it the most.

It's sort of a chicken-or-egg question.

"Is multitasking causing them to be lousy at multitasking, or is their lousiness at multitasking causing them to be multitaskers?" Nass wondered. "Is it born or learned?"

In a society that seems to encourage more and more multitasking, the findings have social implications, Nass observed. Multitasking is already blamed for car crashes as several states restrict the use of cell phones while driving. Lawyers or advertisers can try to use irrelevant information to distract and refocus people to influence their decisions.

In the study, the researchers first had to figure out who are the heavy and light multitaskers. They gave the students a form listing a variety of media such as print, television, computer-based video, music, computer games, telephone voice or text, and so forth.

斯坦福大学研究者得出一个令人吃惊的结论：那些负有多重任务的人往往干不好工作，因为他们更容易分心，和担负工作少的人相比，更不易识别被不相关的信息。

斯坦福大学交流与传播系的教授，克利福德·纳斯在一次电话访谈中说，"研究发现，人们用的媒介越多，就越不容易用好。这使我们非常震惊。"

研究者调查了262位大学生，把他们分为高、低多任务小组，在记忆力、从一个任务到另外一个任务的切换能力和对任务的关注力上进行比较。其研究结果发表在本周二出版的美国国家科学院学报上。

当涉及到这些关键能力时，担任多重任务的人得分没有其他人高，纳斯如是说。

仍待解决的问题是，为什么那些干多重任务差的人是干得任务最多的？

这似乎是"先有鸡还是先有蛋"的问题。

"是多重任务导致他们表现糟糕，还是他们的糟糕表现使他们成为多重任务者？"纳斯考虑道，"这是先天的还是后天的？"

纳斯注意到，在这个似乎鼓励做多重任务的社会环境下，此项发现具有社会影响。车祸已归咎于多重任务，好几个州限制开车时使用手机。律师或广告商可以使用无关信息来分散注意力，并重新关注人们影响他们的决定。

在这项研究中，研究者首先要弄清楚多重任务的轻重之分。他们提交给大学生一个表格，列有一连串的媒介，如印刷、电视、电脑各种媒体的视频，音乐，电脑游戏、电话语音或文字，等等。