There is a distinction made between cognitive multitasking and other so called multitasking, which, involves one cognitive endeavor and some motor process, which relies on muscle memory.
Any multitasking, or, more accurately named, multiswitching is connected by most psychologists to something called executive function, a model developed in 2001 by Ear Miller and Jonathan Cohen. Here is a technical definition of it:
Executive function is a collective name for a number of actions, which are located primarily within the frontal lobes of the human brain. Rather than performing cognitive operations, such as learning, the frontal lobes are concerned with the organisation of capabilities that will be carried out elsewhere in the brain (Baddeley et al 1997). The frontal lobe, therefore, is seen as supervisory or managerial in function.One thing must be made absolutely clear. Some people try to distinguish between multitasking and multi-switching. There is no such real distinction between the two - they are identical. No computer with ONE chip multitasks, if that means working on two things at the precisely same moment. A CPU works on one task at a time and switches between tasks. This scheduling is what is generally called multitasking.
In computing, multitasking is a method by which multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is actively executing instructions for that task. Multitasking solves the problem by scheduling which task may be the one running at any given time, and when another waiting task gets a turn. The act of reassigning a CPU from one task to another one is called a context switch. When context switches occur frequently enough the illusion of parallelism is achieved. Even on computers with more than one CPU (called multiprocessor machines), multitasking allows many more tasks to be run than there are CPUs.****Notice the key phrase, "illusion of parallelism is achieved." This is not the same as true multitasking which is parallelism.
There is one thing that both camps on the issue of multitasking agree. Both agree that the brain can change its neural connection very quickly in a matter of days to reflect the kind information it is being exposed to. This was predicted by Marshall McLuhan in the 1960's and has been confirmed by brain studies performed by Dr. Gary Small. (see footnotes at bottom)
Those Who Do Not Believe in Cognitive Multitasking
The classic test that has been used to measure the effectiveness in "multitasking" is a visual one. Were people are asked to identify consonants or letters while other distractions are going on. But there is an interesting critique of this testing procedure cited by a used in an Scientific American article.
This test only detects a brain process that is effectively dedicated to visual processing. Since humans essentially have a singular visual process using two physical visual sensory input devices, there is little multitasking capability supported (although there are many subtasks that may be associated with it). For example, the two eyes are not independently capable of following two moving objects - unlike some lizards. Conveniently designed experiment! If you could get those lizards to perform the same tasks, you would likely get different results.The commentator goes on to say:
Moving beyond processing dedicated to physical and sensory resource management, humans are quite capable of multitasking many abstract objectives. Unlike these researchers, many professionals have to concurrently manage many ongoing projects - each with ans intrinsic priority and schedule. It must be nice to be able to focus on one experiment at a time!This would not be the first time a defective lap experiment is used to verify what some scientists may have a hunch about.
Nevertheless there are problems that arise with reading extensively on the Internet in your typical browser setting as explained by Nicholas Carr in his new book entitled, The Shallows: What The Internet is Doing to Our Brains:
The need to evaluate links and make related navigational choices, while also processing a multiplicity of fleeting sensory stimuli, requires constant mental coordination and decision making, distracting the brain from the work of interpreting text or other information. Whenever we, as readers, come upon a link, we have to pause, for at least a split second, to allow our prefrontal cortex to evaluate whether or not we should click on it. The redirection of our mental resources, from reading words to making judgments, may be imperceptible to us—our brains are quick—but it’s been shown to impede comprehension and retention, particularly when it’s repeated frequently. As the executive functions of the prefrontal cortex kick in, our brains become not only exercised but overtaxed. In a very real way, the Web returns us to the time of scriptura continua, when reading was a cognitively strenuous act.The reference he makes to scriptura continua refers to the early practice of not putting any spaces between words, since at that time, there was virtually no silent reading, most reading was to be done out-loud to others. There has been a recent discussion about whether links ought to be placed inside the text of a web page. Some view it as distracting. Kevin Kelly and others have suggested making the links invisible until one wishes to see them so as not to get in the way of the reading of the text.
The common view now, is to critique multitasking as a myth. You can watch this Frontline video produced in 8 parts on youtube. I post the first part and you can follow the links from there.
A Defense of "Multitasking"
The humorous thing is, that EVEN if the mind's inability to switch between multiple tasks efficiently was true, it would do NOTHING for ANYONE. The world is headed towards more and more multiple tasks whether the brain is ready or not. Nevertheless there is a place to question whether all that we are getting from our new technology will be good. All these discussions are healthy.
Apparently, not all are equally bad at "multitasking." Those who are bilingual have a better time of it. There is also the rather recent discovery of neuroplasticity, discovered through the pioneering work of Dr. Merzinich. Neuroplasticity states that the brain can reconfigure it neural pathways to fit a task or injury:
The adult brain is not "hard-wired" with fixed and immutable neuronal circuits. There are many instances of cortical and subcortical rewiring of neuronal circuits in response to training as well as in response to injury. There is solid evidence that neurogenesis (birth of brain cells) occurs in the adult, mammalian brain—and such changes can persist well into old age.****More research from the Vanderbilt University has demonstrated that people can be trained to increase their switching abilities with greater efficiency. With such a magnificent organ as the brain is, why should this surprise us? It will become better at it with time. Of course, the "deep reading" argument (see footnotes at bottom) is still a strong one, but perhaps we are being forced to much larger paradigm shift than many are prepared to accept. Perhaps we need to have computers help us with the management of tasks, much like Google imagines when it speaks of thinking a thought and having google give you the answer. Perhaps we need to define an entire new way of learning with this new medium of the Internet. Why are still relying on extensive reading in this new world. To some, this might sound like a betrayal of all that is academic, but they forget that when the book was introduced, people complained of the lessening of the value of public speaking or of a good memory. The book, faced similar opponents. We leave you with an excellent video by Nicholas Carr on this subject. We do not necessarily agree with him on his entire thesis, but nevertheless it is very informative:
Nicholas Carr, The Shallows:What the Internet is Doing to Our Brains
Deep reading is the idea that the brain when doing traditional reading in a paper book, can focus on specific details that normally do not happen when reading on the Internet. This deep analytical state is said to be critical to some academic studies.