Your brain can only do tow tasks at the same time (one task for each half-brain). If you do more than 2 tasks then try to do them 2 by 2. If you try to make 3 tasks at the same time, then things become confusing.
That's what showed the newest results of brain activity researchs :
If you're in a busy job or have lots of things going on at home, you may be embroiled in frenzied multitasking. Most people actually find that they are not very good at it. Don't worry, a new study published in the Journal, Science has found that the brain cannot handle more than two tasks at a time.
There is a part of the brain called the medial prefrontal cortex (MFC), which is in the region of your front brain that manages tasking. It also interfaces with the emotional and cognitive systems of the brain, in addition to giving you your sense of Self. Studies show that this part of the prefrontal cortex interprets meanings of events that are experienced and attaches emotion to them. So when you are multi-tasking you can experience the emotion of frustration or other down emotions if you attempt to add more tasks than the brain can handle.
When more than one task is engaged, the MFC divides into two so that each half manages a task. For example, you can talk on the phone and do your photocopying but you can't add a third task. Things get too confused and chaotic. The brain can very easily manage the two tasks but parts of the tasks get dropped when a third is added. Switching back and forth between the two tasks works fairly well for the MFC but it can't seem to find a place to put the third task.
When the MFC in the two frontal lobes divide, each representing a task, the frontal portion enables the brain to do the switching back and forth between tasks and keeps track of all the related actions on a simultaneous basis. One goal of a task is accomplished while the other task is on hold. Depending on which task you place your attention next will be where the brain directs its signal.
One of the best examples that comes to mind is the job of receptionist. She has to answer the phone, handle customers, deliver messages, do the filing, type reports, organize incoming and outgoing mail, all the while trying to do it efficiently. If she knew she could only accomplish two efficient tasks at a time, she may be able to do them quicker and get on with the next ones, instead of trying to do everything at once.
By working with how the brain works instead of trying to do too many things at once, people may be able to improve their job performance and their job satisfaction. It is important to note that job satisfaction goes a long way to maintaining peak job performance. Studies show that the dorsal and ventral MPFC can be further divided into tasks that demand attention and tasks that are self-referential. Self-referential brain activity occurs when there is reference to emotional processing while doing attention-demanding tasks. In other words, you will default into emotions during times when you are doing a task that demands attention.
Make your job a lot easier and less stressful by attempting no more than two tasks at a time. Realize that emotion is created during times when tasks really command your attention. By reducing stress and improving your enjoyment, you will keep your peak job performance.
source..
These researchs are done by a team of french researchers from the
"Institut national français de la santé et de la recherche médicale (Inserm)", here the article
in french published in "Le Monde" newspaper :
"Pas plus de deux choses à la fois"