We all find ourselves struggling with multiple tasks at the same time: while we are vacuuming we are on the phone or watching TV while we are preparing food. Women are well aware of what multitasking is, that is, the ability to do multiple things at the same time because they are much more capable than men in this practice. Even people who work in the IT field have a high ability to engage in multiple tasks at the same time, dwelling on each of them for no more than two / three minutes before moving on to the other.

Work changes over time: phone ringing, e-mail to answer and in some cases, thanks to smart working, organize the office activity while doing household chores. It has become normal to break life into moments when we dedicate ourselves to several things, in which we manage multiple flows of information from different sources.

Multitasking is part of our life and as such is done with absolute automation; In fact, there are actions that we can carry out in parallel with others without interfering with each other: talking while walking is a common ability, but it is not possible to eat and speak because it is dangerous. Even on a cognitive level we can perform multiple tasks simultaneously such as drawing and fantasizing or talking but it is much more difficult for example: memorizing lists of numbers and following a light on a computer screen, this because remembering verbal stimuli and memorizing a moving object activate functions cognitive not exactly superimposable.

One action that requires more resources than the other will penalize the second. Like when we slow down while walking and chatting we find ourselves expressing a complex concept. The inability to carry out two complex tasks cognitively must make us reflect, especially when we drive and pretend to speak on a cell phone; an extremely dangerous thing because the two activities cannot be superimposed, one of the two is affected and probably it will be the driving that will be “automated” to reduce reaction times. Even the use of the headset while driving has few virtuous effects; the concept is that the attention needed to process the driving stimuli is directed to the phone call for which the inputs are detected: signals, traffic lights, obstacles but the reaction to them: deceleration, braking, changes of direction are processed more slowly causing disastrous effects that are independent of phone manipulation. Therefore it would be more prudent to avoid any distraction when you are behind the wheel: eating, playing with the car radio, smoking, listening to loud music.

But why does this happen if we are often able to carry out multiple activities at the same time? One answer may be related to the fact that the brain has “limited capacity”. Approximately the human brain has about 100 billion neurons that thanks to synapses, axons and innumerable interconnections communicate with each other in a few milliseconds. But this is not enough: when the information to be processed is complex, the circuit suffers, similarly to a computer processor which despite its high computing power can slow down if the operations to be carried out are too complex.

The limits meet especially when we need to process sensory information and take action. Already in the phase of recognition and decoding of the stimulus we find the first limit. In fact, the two visual events that occur and at the same time will be subjected to our attention (ie cognitive processing) with a difference of more than half a second from each other. So discriminating two different stimuli presented in succession takes time.
The second limit can be found in the information maintenance and monitoring phase. Also in this case we can hardly notice the change of two situations, scenes or the same stimuli if visual elements of disturbance take our place while we perceive them.

Finally, in the response to external stimuli that arise quickly there is a third limit called the “refractory psychological period” and this entails a slower response to a second stimulus presented in rapid succession to the first.
On balance, the numerous stimuli to which our brain is subjected cannot all be processed, therefore it chooses only a part to be stored selectively and for the interest we have in a given stimulus. Similarly, when two people talk to us at the same time, we choose to listen to only one while ignoring the other; it would be impossible to listen to both.
The amount of attention to be paid to each input we receive or to each task we perform are determined by the “Central Executive System”, a set of neurons located in the frontal lobes. This system also plans the execution of the tasks to be performed and the information to be processed allowing us to switch from one task to another with ease (similar tasks), or with difficulties (different tasks). Changing tasks requires a series of mental operations that take place unconsciously and have a duration that grows with its difficulty. For this reason, driving should be an action done in a unique way, without “dedicating” yourself to anything else in the meantime.

Switching from one task to another or from one action to another can lead to an interruption; however contrary to popular belief it is not said that an interruption can have disturbing effects. It can even facilitate the performance of a task if it acts as a warning to better review its objectives, it could in fact represent a useful and functional strategy rather than a useless distraction.
Speire et al. (1999) decreed that simple tasks are completed faster after an interruption without affecting their accuracy. So most people would be able to deal with short breaks even while they are doing multiple activities in parallel.

In conclusion, we can say that our brain has remarkable ability to process multiple information simultaneously. This allows us to carry out activities in parallel, in multitasking; but it is neither easy nor simple. However, if the conditions are advantageous, if we are adequately trained, if we are committed, we may be able to produce multiple activities and behaviors or tasks simultaneously. But the question that arises is: “Do we really need it?”.