The Overflowing Brain: Information Overload and The Limits of Working Memory (2009)
Torkel Klingberg (1967- )
Who in these days of cell phones, digital assistants, and other high-bandwidth devices has not felt at times that they just cannot keep up with the flow of information? Has not felt overwhelmed to the point of feeling like a kind of mental grid lock has set in? And has not wondered whether there is not something wrong with their brain, that it doesn't seem able to keep up?
Over a fast-paced and engaging 200 pages, Torkel Klingberg, a professor in cognitive neuroscience, reviews what recent research, including his own, reveals about where the bottleneck is in the brain for processing incoming information, about how distractions, fatigue and the amount of incoming information affect the restrictiveness of this bottleneck, and whether we can train our brains to expand our ability to process information. What follows here is a brief review of the topics Klingberg presents, although some of the fascinating parts of the book are his detailed descriptions of the set-up and results of a variety of studies that have been performed, and which I only summarize.
Klingberg first reviews some of the basic terms around which the rest of his discussion evolves. He lists three types of attention: controlled attention, such as when focusing on reading a report; stimulus driven attention, such as when our attention is drawn to an event occurring in our surroundings; and arousal, which is general, active attention, such as monitoring a radar screen. He then focuses on the first two of these, controlled and stimulus-driven attention, and their interaction, such as when someone is reading a report, using their controlled attention, and is distracted by an event that activates their stimulus driven attention (in Klingberg's example, someone nearby dropping a coffee cup). He describes the results of recent research using functional Magnetic Resonance Imaging on people's brains as they perform different cognitive tests. This testing has shown that controlled attention and stimulus driven attention activate different parts of the brain, and so function independently. Since they function independently, it stands to reason that they should not be limiting each other; however, everyone has experienced the competition between these two types of attention --- in the earlier example, most of us are unable to remain focused on the report we are reading, if nearby a coffee cup smashes on the floor. Since these things are handled by different areas of the brain, why are we so easily distracted?
To answer that question, Klingberg introduces the concept of working memory, which "refers to our ability to remember information for a limited period of time, usually a few seconds." (p. 33) He describes research that has shown that a person's working memory can typically hold and reproduce accurately about seven pieces of information, a concept that he says was first introduced in 1956 by George Miller in his article The Magical Number Seven, Plus or Minus Two: Some Limits on our Capacity for Processing Information. It has been shown that this number varies slightly from person to person, and even for a given person depending on the level of distractions, tiredness, age and other factors. Klingberg states that this "capacity limitation of working memory is one of the things that distinguishes it from long-term memory." (p. 35) He illustrates the difference using the example of going to the grocery store: a person encodes in long-term memory the location of their parked car for retrieval of the location when they leave the store, but uses working memory in the store, when searching for a particular item, such as a gallon of milk. He also reviews what has been found about the effect of the limitation of working memory on our ability to process information. As a particular example he describes studies that have found a substantial delay in the reaction time of people talking on their cell phone while driving --- or even just holding conversations with someone in the car while driving. A similar delay has not been found in these studies when the driver is doing more passive activities such as listening to the radio or an audio book; it is the need to focus on a conversation that limits the working memory's ability to effectively support driving at the same time.
Having established working memory as the limitation, or bottleneck, in the brain's ability to process information, Klingberg devotes the remainder of his book to various aspects of working memory. He first reviews research that has shown that the capacity of a person's working memory is a strong indicator of that person's problem solving ability, and describes models being developed and evaluated for how the working memory may function. He also takes a brief look at theories of how intelligence developed in humans, and why the limitation in working memory may have developed as it did; not surprisingly it is difficult to come to firm conclusions on such discussions. All of this serves as background for the central questions of the book: can the brain be trained to improve working memory, how would it be done if it is possible, and whether and how effectively our daily activities contribute to such training.
Klingberg cites a host of studies that have shown the brain's plasticity in this regard --- the ability to improve its working memory and so problem solving ability through training. Many of the studies on training the working memory have involved children diagnosed with ADHD (Attention Deficit and Hyperactivity Disorder), and he provides a brief introduction to it, focusing for the most part on ADD, the attention deficit aspect of the disorder. He notes that ADHD is not a 'have it' or 'don't have it' condition: "most scientists see the degree of symptom as being normally distributed among the population … mean[ing] that rather than there being a discrete little group of people with attention deficits standing isolated form the healthy masses, there are really only difference of degree." (p. 107) He refers to studies that have shown that people who suffer form acute ADHD have deficiencies in their working memory. Having described earlier in the book how distractions reduce the effectiveness of working memory, this leads to one approach for people with ADHD: to reduce the distractions from their environment, in effect making the amount of working memory capability that is available to them as effective as possible. But his larger interest is in the area of improving the existing working memory; he concludes his look at ADHD with the question: "Can we not also attack the other front as well [and] increase our mental capacity?" (p. 114)
Klingberg opens his discussion on training by pointing out that research has shown that not all training is equal in terms of its effectiveness on improving working memory. He cites research results that show that, for example, someone training to become better at remembering numbers can improve, but that improvement doesn't translate into an improved working memory in other contexts. (He attributes this at least in part to people doing this type of training often developing strategies to remember combinations of numbers as a single unit, and so they are not only, or primarily, improving the number of units of information that can be stored in their working memory.)
Based on those results he narrows his focus to studies that show a general improvement in working memory and so problem solving skills, that is transferable to activities other than the training activity itself, and that results in a measurable improvement in problem solving skills. This then ties in to his discussion on ADHD: in several different studies of children with ADHD, results have shown that "working memory was trainable and that the training had secondary effects" (p. 119). That is, it had an effect even after the training was stopped, and it improved problem solving skills. Studies on the elderly and also people not diagnosed with severe ADHD have shown similar results.
The training that was used in these studies was non-specific type training (as opposed to, say, memorizing numbers), and Klingberg then looks at our busy daily lives and rhetorically asks, "[we use] our working memory throughout the day. Should we not therefore be constantly exercising our working memory so that it progressively improves from one day to the next?" (p. 125) Referring to studies that looked at the effectiveness of various levels of complexity in training, he concludes that only training that pushes the working memory to the limits of its capability on a regular basis is effective; less aggressive training shows little benefit. "[A 5 year study of senior citizens found] that reading, chess, playing a musical instrument, and dancing were all associated with a later, relative improvement of cognitive ability and a lower risk of dementia [but] only if the activities were done several times a week.... [P]hysical exercise … had, on the other hand, no effect at all on mental health." (p. 127) Thus, the type and complexity of training (or more broadly 'activity') is critical, but also the amount of time regularly spent on such activities plays a key role; simply using the working memory during our daily lives is not sufficient to improve it.
Klingberg also looks briefly at the other side of the coin, attention or concentration, discussing investigations that have shown that meditation can improve the ability to concentrate. The studies that have been done, and that he describes in some detail, have involved people who spend many hours per day meditating, such as monks. He describes the results obtained to date as inconclusive.
He devotes an entire chapter to the issue of computer games and the question of whether they are a negative influence or a positive one (in terms of cognitive ability --- he sidesteps the 'violence debate') . He points out that there is no general answer, referring back to the earlier discussion: some types of training are more effective than others, and it is critical that the working memory be pushed to its limit repeatedly. Thus it is critical to consider particular computer games, instead of trying to make a general statement about computer games as a whole. He describes a variety of studies that show some types of computer games as having a positive influence on cognitive skills.
He also looks briefly at medication that is being developed with the intent of improving cognitive ability. Although medication has been shown to have some positive effect, he comes down on the cautious side, raising concerns about the unknown side effects, particularly long-term, of such an approach. His preference is "a greater focus on mental health care in the form of mental gymnastics." (p. 162)
Klingberg concludes with a short chapter on the "information flood" that exists today and studies of its effects on cognitive ability. The results of some of these studies point to a kind of 'sweet spot' of information flow --- we perform best when the challenge presented is just at the limits of our skill. He refers to a diagram developed by Mihály Csíkszentmihályi, who defines 'flow' as "characterized by a high level of challenge and skill, in which the capacity of the doer exactly matches the demands of the task being done.... [W]hen challenge exceeds skill, we get stress. When skill exceeds challenge, we get a sense of control, which becomes boredom as the level of challenge drops." (p. 168)
In The Overflowing Brain, Torkel Klingberg provides a fascinating look at an aspect of our brain function that affects our everyday activities. His writing style is engaging without giving the reader the feeling that he is dumbing-down the subject. His approach of tying each topic to an example that most of us can easily relate to helps ground the discussion for those of us not experts in neurology, and yet he provides enough detail to satisfy a lay-person interested in broadening their scientific understanding. As you return from reading the book to work or other daily activities, it is not hard to find connections to what you have just learned in your attempts to juggle e-mails, instant messages and cell phone calls, while completing the task on which you had planned to focus all of your attention.
Other reviews / information:
David Glenn, in The Chronicle of Higher Education; includes quotes from professors wrestling with computers in the lecture hall.
Story on NRP: To Keep Your Brain Nimble As You Age, Stretch It