Do you read while listening to music? Do you like to watch TV while finishing your homework? People who have these kinds of habits are called multitaskers. Multitaskers are able to complete two tasks at the same time by dividing their focus. However, Thomas Lehman, a researcher in psychology, believes people never really do multiple things simultaneously. Maybe a person is reading while listening to music, but in reality the brain can only focus on one task. Reading the words in a book will cause you to ignore some of the words of the music. When people think they are accomplishing two different tasks efficiently, what they are really doing is dividing their focus. While listening to music, people become less able to focus on their surroundings. For example, we may have experienced times when we talk with friends and they are not responding properly. Maybe they are listening to someone else talk, or maybe they are reading a text on their smartphone and don't hear what you are saying. Lehman called this phenomenon 'email voice'.

The world has now changed by computers and their spin-offs such as smartphones or cellphones. Now that most individuals have a personal device, like a smartphone or a laptop, they are frequently reading, watching or listening to virtual information. This increases the occurrence of multitasking in our day-to-day life. Nowadays, when you work, you may use your typewriter, your cellphone, and speak to colleagues who may drop by at any time. In professional meetings, when one would normally focus on and listen to one another, people are more likely to have cellphones in their lap, reading or communicating silently with more people than ever. Even a telephone such as the cordless phone increased multitasking. In the old days, a traditional wall phone would ring, and the housewife would have to stop her activities to answer it. When it rang, the housewife would sit down with her legs up and chat, with no laundry, sweeping or answering the door. In the modern era, our technology is convenient enough not to interrupt our daily tasks.

Earl Miller, an expert at the Massachusetts Institute of Technology, studied the prefrontal cortex, which guides the brain while a person is multitasking. According to his studies, the size of this cortex between species. He found that for humans, the prefrontal cortex constitutes one-third of the brain, whereas it is only 4 - 5 percent in dogs and about 15 percent in monkeys. Because this cortex is larger in humans, it allows a person to be more flexible and accurate in multitasking. However, Miller wanted to know whether the cortex was truly processing information about two different tasks simultaneously. He designed an experiment in which he presented visual stimuli to his subjects in a way that mimicked multitasking. Miller then attached sensors to the patients' heads to pick up electrical patterns of the brain. These sensors would show whether the neurons were truly processing two different tasks. What he found was that the brain neurons lit up in singular areas one at a time—never simultaneously.

David Meyer, a professor at the University of Michigan, studied young adults in a similar experiment. He instructed them to solve math problems while simultaneously classifying simple words into different categories. Meyer found that when you are doing several jobs at the same time, you are actually switching between jobs. Even though the participants tried to do the tasks at the same time and both tasks were eventually accomplished, overall the task took more time than if the person had focused on a single task.

People sacrifice efficiency when multitasking. Gloria Mark used office workers as her subjects. She found that they were constantly distracted. She observed that nearly every 11 minutes people at work were disrupted. She found that doing different jobs at the same time may actually save time. However, despite the fact that they are faster, it does not mean they are more efficient. We are equally likely to be interrupted as to be interrupted by outside sources. She found that in the office nearly every 12 minutes an employee would stop, with no reason at all, check a website on their computer, call someone or write an email. If they concentrated for more than 20 minutes, they would feel distressed. She suggested that the average person may suffer from a short concentration span. This short attention span might be natural, but others suggest that new technology may be the problem. With cellphones and computers at our sides at all times, people will never run out of distractions. The format of media—such as advertisements, music, news articles and TV shows—is also shortening, so people are used to paying attention to information for a very short time.

Even though focusing on a single task is the most efficient way for our brains to work, it is not always practical in real life. According to human Edward Hallowell, people feel more comfortable and efficient in environments with a variety of tasks. He observed that people are losing a lot of efficiency in the workplace due to multitasking, outside distractions and self-distractions. In fact, the changes made to the workplace do not have to be dramatic. No one is suggesting we ban email or make employees focus on only one task. However, certain common workplace situations—such as group meetings—would be more efficient if we banned cellphones, a common distraction. Instead of arriving at the office and checking all of your e-mails for new tasks—a common ritual—you could dedicate an hour to a single task first thing in the morning. Self-timing is a great way to reduce distraction and finish tasks one by one, instead of slowing ourselves down with multitasking.