The term “multitasking” originally referred to a computer's ability to carry out several tasks at one time. For many people, multitasking has become a way of life and even a key to success. In fact, some excellent mental aerobic exercises (大脑训练) involve engaging the brain in two or more challenging activities at a time. Although checking e-mail while talking on a phone and reading the newspaper may be second nature for some people, many times multitasking can make us less productive, rather than more. And studies show that too much multitasking can lead to increased stress, anxiety and memory loss.
In order to multitask, the brain uses an area known as the prefrontal cortex (前额叶脑皮层). Brain scans of volunteers performing multiple tasks together show that as they shift from task to task, this front part of the brain actually takes a moment of rest between tasks. You may have experienced a prefrontal cortex “moment of rest” yourself if you've ever dialed (拨电话) a phone number and suddenly forgotten who you called when the line is answered. What probably occurred is that between the dialing and the answering, your mind shifted to another thought or task, and then took that “moment” to come back. Research has also shown that for many volunteers, job efficiency (效率) declines while multitasking, as compared to when they perform only one task at a time.
Multitasking is easiest when at least one of the tasks is habitual, or requires little thought. Most people don' t find i t difficult to eat and read the newspaper at the same time. However, when two or more attention-requiring tasks are attempted at one time, people sometimes make mistakes.
We often don't remember things as well when we're trying to manage several details at the same time. Without mental focus, we may not pay enough attention to new information coming in, so it never makes it into our memory stores. That is one of the main reasons we forget people's names—even sometimes right after they have introduced themselves. Multitasking can also affect our relationships. If someone checks their e-mail while on the phone with a friend, they may come off as absent-minded or disinterested. It can also cause that person to miss or overlook key information being passed on to them.
追答“多重任务处理”这个词原意是计算机同时执行几个任务的能力。对很多人来说，一心多用，已经成为一种生活方式，甚至是成功的关键。实际上，一些很好的大脑训练就涉及到让大脑一次接受二个或更多个挑战。虽然对某些人来说，一边查邮件，一边接电话，同时还看着报纸，似乎是他们的第二天性，但很多时候，一心多用往往会降低而不是提高效率。研究表明，一心多用会导致压力增加、焦虑和记忆力减退。
要同时处理几件事情，大脑会使用前额叶脑皮层。对志愿者大脑扫描显示，从一件事情转到另一件事情时，大脑前部会在任务转换时休息片刻。如果你拔完电话，对方接了以后，你突然忘了在给谁打电话，那你可能就经历过前额叶脑皮层的“休息片刻”。在你拨电话和对方接电话之间，你的脑子可能转到另一个想法或另一件事上去了，所以需要“休息片刻”回到打电话这件事上来。研究还发现，对很多志愿者来说，一心多用，与他们一次只做一件事情时相比，工作效率下降了。
如果同时做的几件事中，至少有一件是习惯性的或者不太需要思考的，那是最容易的时候。大多数人都不会觉得边吃饭边看报纸有困难。但是，同时做两件或多件需要留神的事情时，人们往往会出错。
同时处理几个细节问题时，我们常会忘事。精神不集中，可能对新的信息注意力就不够，于是这些新信息就根本没贮存到记忆中去。这就是我们会忘记别人名字的主要原因之一——有时甚至人家刚介绍完就忘了。一心多用也会影响我们与别人的关系。如果有人边查邮件，边给朋友打电话，可能会显得心不在焉或对别人的话不感兴趣。他也可能会漏掉或没注意到别人告诉他的重要信息。