Human real-time operating system theory?

November 16, 2010 § Leave a comment

Multitasking and human interrupt processing

Imagine someone walking down the stairs with a glass of beer in hand, and then suddenly dripping over and falling down. It would be a natural reaction to forget the beer glass, try to recover balance,  and try to avoid hurting oneself. Most of us would drop the glass and spill the beer all over because it is more important to survive the fall than to save the beer. Somehow in our minds we are able to open the gates to this new and high-priority behavior that can save us from serious damages. But how does this happen? How can we know which part of the current behavior must be stopped, how do we replace it and which one of the many potential behavior patters should we choose for this specific situation? Some part of the present activity must apparently be preserved and continued, but which part?All this has to happen extremely fast.

Switching the context

This is a typical case of human interrupt processing (HIP) that happens to us, in some form, all the time. In other words, our ongoing behavior is interrupted and other, more relevant processes are allowed to access our available mental resources. In this specific case the context of walking down the stairs, with a glass of beer in hand, in a mood of enjoyment, and with the aim of watching television, for example. It means that a significant part of our mental resources are allocated for dealing with that context, that is, performing the relevant task.  In this example case, that content becomes suddenly replaced by an accident context that requires completely different data and resources.

This change is called a context switch in the operating system theory to describe a situation where the contents of the available resources (registers) are replaced by a new content that is relevant to the specific context at hand. One could say that then the content of the registers/resources is the context. This change of resource contents is based on the privilege structure that allows some crucially important tasks to be performed so that they overrun the less important ongoing activities for a short period of time. Sometimes, in extremely important situations, it might be possible to have a temporary direct access to memory and processor resources, and even ‘stealing’ time and processing power from them.

In order to perform such important and privileged tasks, the required resources must be refreshed to match the needs of the task to be performed and everything must be extremely well coordinated. In a threatening situation, one can think that all the available resources are refreshed to match the requirements of the new context.  Psychologically, it is a good question what are the resource contents that are needed in each context, how should they be described, and what is this coordination process like? There is no generally accepted, formal psychological language to describe this complex process and architecture.

Energy flow during the context switch

Interestingly, the context switching process is subjectively a very energetic experience and one can feel the flush of energy involved in focusing all our available resources to the new task demands and in orchestrating the required activities to accomplish it. In the beer example the threat of hurting oneself was of such a high priority that it could override many ongoing activities, but of course, not all.

Perhaps it is also because of this energy usage, that continuous, unnecessary interrupts are so energy-consuming and burdening to us in our normal (especially work) life. I have not seen a calculation of how much brain energy is required by a context switch, but it must by quite a lot, compared to any other mental process. This could be an invitation to brain scientists to look at the entropy measures in the cortical and other brian activities. But of course, some processes/tasks are so crucial for our body and mind that they need to have the highest priority at all times. These can be compared to the operating system kernel (the core of the operating system sw that maintains the connection between the computer, its memory, devices connected and its environment) functions and prioritized hard-wired interrupts used in computer operation and in related device services. If the kernel is damaged, nothing can work properly. This offers many evident analogies to human behavior.

We are extremely skillful in the interrupt processing and it is one of the secrets of human survival in complex and unpredictable environments. One could claim, that interrupt processing is a crucial element behind our intelligent behavior. In everyday life it creates an illusion that we are genuinely performing multiple tasks at the same time. But it is a matter of temporal scale and resolution: we use dynamically our available, but limited perceptual, cognitive, and affective resources. When sudden changes take place in the situation and/or several demands for resources occur simultaneously, this limitation is revealed. The same is true with the operating systems of our computers.

Real Time Operating System Thinking

The design of real time operating systems (RTOS) is a most fascinating field to a serious psychologist who wants to understand how people manage to perform numerous intelligent activities and survive in the complex word. You can find an inspiring introduction and sources to the topic from

What is this process of context switch in the human mind? Can it be characterized as a process where the essential contents of our consciousness, our mental ”registers”, undergo a content change so that their old content becomes replaced by a new one that represents the requirements of the new context?  If the demands of the new context can be successfully met, a balance is achieved, and the previous context (and ”register contents”) can be recovered and it is again possible to continue the behavior according to the earlier context. But where do these new contents come from? Have they been stored somewhere or is it just a mater on refreshing the links to them? Where does the old context information go? What is replaced and what is new? What is this process like? Is it typical for all of our behavior, that are sensory, cognitive, artistic, and even spiritual in nature?

Anyone can observe the amazing effectiveness of these processes and their extensive scope, when starting to read a novel, for example. ”He was an old man who fished alone in a skiff in the Gulf Stream and he had gone eighty-four days now without taking a fish”.  A few words are enough to induce a complete context switch in our minds and we move to the strange world of this fisherman – by Ernest Hemingway.  This is not only a cognitive switch but deeply emotional, cultural and spiritual. It is not a 1-1 process. Why is this so effective?

To schedule is human

Because we live in a complex world and in a demanding, multiple-task environment we also need strategic organization of our activities. We cannot effectively perform any umber of tasks simultaneously.  Of course we can do many things by preparing internal and especially external task lists that we simply follow. But even this is a strategic challenge for a human (and computer) operating system: how to use our mental resources in a coordinated and most efficient way?   And what is “effective”? This change is reflected in the design of the scheduling system in the operating systems.  Scheduling of tasks can consist of coordination, re-organization, and keeping up track of ongoing tasks and activities and their scheduling and re-scheduling. Priorities occur there as well, but they control the access to the main computing resources on a more strategic level. Scheduling systems are designed for a purpose, and so it probably is also with he human operating system as well.

For human sciences the conceptual approach to RTOS is extremely valuable. One would like to see more this kind of analysis in the theory of human attention. Cognitive science literature should indeed include a thorough introduction to these fascinating and inspiring topics. For example, in order to design optimal operating systems, it has become necessary to develop a structural and architectural approach and concepts that allow the analysis and control of computer performance in a complex, varying  task environment. On the other hand, RTOS theory reflects the structure of the present-day computers and their cpus, memory, and i/o structures. It is not be wise to extend this analogy very far for the study of the human operating system. With new computer architectures, new RTOS theories will follow. But I would still like to see a well-defined architectural description of the Human Real Time Operating System structure and main principles. It is possible that I have just missed it, perhaps it has been described somewhere. I do have to admit that I have not followed this research accurately lately, but apparently nobody knows exactly the dynamics and information processing structures related to this complex process. But I still believe that this problem has not been well defined as of yet.

But are we similar?

Interesting enough, we are different in our capacities to deal with such demanding context changes. The example case I mentioned above, ended up with a surprising outcome because it happened to a person with a strong sports background where falling down is not an extreme and not even a dangerous event. One could say that he has developed himself a specific interrupt structure So, in fact he did not spill his beer completely and did not drop the glass, but instead, he hurt his back ribs quite badly. Why? Because he had a relevant process available, somewhere in his cognitive repository and a way to switch quickly to this context of managing the two things together – saving the beer (and the carpet, perhaps) and not hurting seriously himself. But something went wrong and he hurt himself so much that it would have been bad on the football field as well. Here the context was not a football game, but perhaps there was something that triggered the specific survival behavior, that now was a bit ‘out of context’?  Apparently, we have very different multitasking processing capacities, and a good question is: do we all have similar processes in dealing with these context switches? Or is it possible that people develop different mental architectures, and even strategies for this purpose? But clearly, these example mechanisms are not hard-wired, but some certainly are.

The example case shows that we have a repository of actions at our disposal. But how are these repositories organized? How do we now which activities to initiate when there is not enough time to run a comprehensive losses-gains analysis or when the situational requirements suddenly change, perhaps in a time less than half-a-second?

Multi-taskers are poor cognitive performers

Clifford Nass and his research group from Stanford have demonstrated that subjects with high-multitasking behavior tend to have a surprisingly low cognitive performance in simple cognitive-attentive tasks.  While this has many implications, it is interesting to consider this kind of results in the light of interrupt processing theory that has been applied in computer operating systems. Apparently, at least some alternative theories can be suggested to explain the differences found between low and high multitasking subjects.

It s somewhat surprising the cognitive psychologists have not developed a comprehensive theory of human multitasking behavior. Related approaches have been presented under the topics of working memory, attention and limited-capacity processing considerations. But as far as I know, they do not include real-time operating system architectures, priority analysis, task-lists and scheduling, or dynamic interrupt processing models or frameworks.  Perhaps the concept of ”real-time operating system” does not sound so sexy today when it is a self-evident part of any computer system. Perhaps it is just this fact has made it nearly invisible in the eyes of computer users: our computers appear perform multitasking quite efficiently, and some of us have that illusory ability as well.


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