Collins Kariuki, Neuroscience, Spring 2021
Figure: Shows the human brain and its various parts. Researchers have shown that a select group of individuals – supertaskers – utilize the Prefrontal Cortex (shown above) and the Anterior Cingulate Cortex (not shown) to maintain their goals during multitasking (Source: Wikimedia Commons).
Understanding the human brain is arguably one of the most fundamental goals in science, not only for neuroscientists but for scientists in other fields as well, including computer scientists and linguists . Studying the brain helps computer scientists better model Artificial Neural Networks (ANNs), machines that mimic human intelligence at the cognitive level by replicating the role performed by neurons in a machine-like setting. ANNs can be used in security through advanced face and speech recognition and medicine through gene prediction (Krogh, 2008). Scientists in the 20th century reached a consensus that at least basic sensory and motor functions reside in specialized brain regions, an argument (in part) for the functional specialization of the brain (Kanwisher, 2010). So, in the context of such a profound behavior like multitasking, it would be beneficial to experimentally determine which part of the brain is responsible for this trait. Doing this would take us a step closer to understanding the mechanisms that support maximized productivity. In 2014, Medeiros-Ward, Jason Watson and David Strayer, psychologists from the University of Utah, sought to investigate the neural mechanisms that underlie efficient multitasking. They investigated which part of the brain is responsible for efficient multitasking, specifically for people, they called “supertaskers” (Medeiros-Ward et al., 2014).
According to the American Psychological Association (APA), multitasking refers to the simultaneous undertaking of two tasks (APA, 2006). Multitasking is a common trait among human beings, and it is viewed as a time-saving tool to being more productive. While multitasking can indeed “save time” for some of us, it is usually accompanied by contact switching costs, which refers to the apparent loss in productivity (doing poorly in either task in terms of completion time) while conducting two tasks concurrently. Rogers and Monsell, from the University of Cambridge, showed that switching between simple cognitive tasks results in error rates (less productivity) for most individuals (Rogers & Monsell 1995; APA, 2006). However, in 2010, Watson and Strayer showed that despite there being a perceivable loss in performance during dual-task paradigms, there are individuals, aptly named “supertaskers”, who show no discernible loss in performance during multitasking (Watson & Strayer, 2010). Their study highlighted that there are individuals who perform tasks without loss in performance. Watson and Strayer offered evolutionary perspectives on this basis: this desired trait may not yet have propagated through the population, and as such, we might not directly notice many of these supertaskers in our midst. Their experiment, while providing conclusive evidence of the existence of supertaskers, provides no answer to the question: “What is the neuronal basis for efficient multitasking?” Answering this question, in the context of neurobiology or neuroimaging research, might at least explain what makes these supertaskers able to supertask.
While no mention of supertaskers occurred before Watson and Strayer’s study on the identification of supertaskers, various cognitive scientists embarked on studies to prove the neurological cause of what makes high performers perform better than the average crowd. One such popular study was conducted by Jaeggi et al., from the University of Bern in Switzerland. In their study, Jaeggi et al., sought to answer: “What happens in the brain when we reach or exceed our capacity limits?” or “What differentiates high performers from low performers at the neuronal basis?” They embarked on performing fMRI tests on individuals as they did a cognitively demanding task: the renowned n-back task, famous for revealing individual differences in areas such as working memory and attention. The n-back task entails presenting stimuli to subjects (usually olfactory and visual stimuli). The participants are required to monitor the stimuli and give a response when they notice a similarity in the presentation of the stimuli, that is, they are required to give a response (usually by pressing a button) when they notice that a certain stimulus was presented n-integers ago. Jaeggi and her team evaluated 22 areas of interest in the participants’ brains when they performed the challenging n-back task. Generally, they found that the brains of high performers “keep cool” during cognitively demanding tasks; that is, minimal areas of the brains of high performers are employed when carrying out cognitively demanding tasks. What’s more is that specific parts of the brain were recognized as important in mediating difficult tasks: an increase in activation was observed in lateral prefrontal areas more so the Left Prefrontal Cortex (LFC). With the Prefrontal Cortex (PFC) playing an important role in mediating intellectual and executive functions in humans such as task-related stimuli and working memory, it should come as no surprise that high performers recruit this specific part of their brains (Lara & Wallis, 2015). Albeit paradoxical, these results could be explained by the fact that high performers use the required parts of their brain (their lateral prefrontal areas) much more efficiently when compared to their middle and low performer counterparts by recruiting as little of them as possible. A trait that could be likened to the efficient rather than haphazard utilization of resources (e.g., money) that we use to accomplish certain tasks (e.g., saving for college) (Jaeggi et al., 2007).
Medeiros-Ward, Watson and Strayer investigated this effect by employing a dual n-back task that presented olfactory and visual stimuli to supertaskers (earlier identified in Watson and Strayer’s 2010 study) against lower-performing controls. They found that the “cooling effect” applied to supertaskers as well. Additionally, they found that the Anterior Cingulate Cortex (ACC) was also recruited when performing the rigorous dual n-back task (Medeiros-Ward et al., 2014). The ACC is known for mediating emotions, this could explain why supertaskers also “keep cool” while engaging in cognitively demanding tasks, essentially avoiding all distractions and detecting errors that conflict with the task at hand (Stevens et al., 2011). Moreover, Jean-Claude Dreher, from French National Centre for Scientific Research, and his team found that damage to the frontopolar cortex, which is part of the larger prefrontal cortex, the area of interest identified by both Jaeggi et al., and Medeiros-Ward et al.,) causes a decrease in performance in multitasking paradigms (Dreher et al., 2008). This is more evidence that the PFC region is crucial in maintaining goals, especially in multitasking.
In the grand scheme of things, Medeiros-Ward et al.’s study and Jaeggi et al.’s study help to shed light on the individual neuronal differences between common low performers and supertaskers. Specifically, the studies support the functional organization of the brain in controlling human behavior. They shed light on emergent theories in psychology such as functionalism concerned with the adaptive functions of the human brain to its environment and evolutionary psychology (“Functionalism”, n.d.; Downes; 2021). Still, many questions arise as to how these supertaskers “keep cool.” It may be nice to determine how average individuals could leverage the FPC-ACC system in conducting not only dual tasks but also single difficult tasks. Hopefully, ANNs could be modelled to mimic this “super tasking effect”. Someday perhaps, humans might all be able to concurrently perform tasks much more efficiently as the environment around us becomes more demanding. A sort of trait that natural selection might perhaps help spread across our species. This remains to be seen.
References
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