What does this mean in practice? Consider a recent experiment at UCLA, where researchers asked a group of 20-somethings to sort index cards in two trials, once in silence and once while simultaneously listening for specific tones in a series of randomly presented sounds. The subjects’ brains coped with the additional task by shifting responsibility from the hippocampus—which stores and recalls information—to the striatum, which takes care of rote, repetitive activities. Thanks to this switch, the subjects managed to sort the cards just as well with the musical distraction—but they had a much harder time remembering what, exactly, they’d been sorting once the experiment was over.
Even worse, certain studies find that multitasking boosts the level of stress-related hormones such as cortisol and adrenaline and wears down our systems through biochemical friction, prematurely aging us. In the short term, the confusion, fatigue, and chaos merely hamper our ability to focus and analyze, but in the long term, they may cause it to atrophy.” (The Atlantic)
I was pointed to this article by kottke, who comments that, if he ever thought he was a multitasker, he was disabused of the notion after he had a child. My wife said the same thing after our son was born. Even going out to ‘kid-friendly’ social occasions was no fun for her, because of the stress associated with dividing her attention as called for when you care about paying attention to your child. That sounds like what is being described above. On the other hand, I was never distressed in those and similar situations. Clearly, some parents can socialize without dividing their attention… by ignoring their child’s interruptions of ‘adult conversation.’ But I never felt that was my story. Whenever the neuroscientists describe generalize about how ‘people’ do such and such a task, I always append the word ‘typically’. There is a spectrum of ability and dysfunction. Some people are better multitaskers than others. As I am sitting here writing that sentence, I am simultaneously thinking that it is not earthshattering news; indeed, it is probably a truism.
There is probably nothing special about the capacity of multitasking to “wear down our system through biochemical friction.” Readers of FmH will know I refer from time to time to the emerging understanding that stress hormones mediate actual tissue damage in the CNS, whatever the source of the stress. If multitasking is stressful or depressing to you, the demand to do it will wear you down. If you are more successful at it and not as stressed out, it will not wear you down, or not as much.
Certainly, in a modern world in which multitasking demands impinge on us more, vulnerabilities which exist in the population will be brought out. A new sort of selective pressure is being brought to bear on mental fitness. But I think the more significant finding of the research described above is the conclusion that multitasking demands we concentrate on the act of concentration rather than the content of the task, i.e. shifting activity from the hippocampus (which places significance on experiences and facilitates their storage in memory) to the striatum. But wait a minute. Is it necessarily a dire outcome if we do more things by rote in a world which enforces certain rote routines on us? It seems to me the key to successful multitasking is being strategic in picking which tasks you multitask at. It is simple — multitask at the rote tasks. But this is no new insight and it did not take functional MRI to tell us — there are certain tasks you must do with heart and attention and others you can do by rote, and you must take care to choose wisely. A simple example — someone can always tell, talking to me on the phone, if I have a computer screen open in front of me and am dividing my attention between reading and talking. It takes some care not to let the onscreen material be compelling and steal my attention at the moment I should be giving my heart to the person to whom I am talking. I have to look away from the screen or close my eyes.
One of the absurdities of the current romance with the reductionist concept of attention deficit disorder is that the control of attention is a complex multifaceted process with many parameters and many ways to be deficient. We have to sustain our attention, focus it, avoid distractions, shift flexibly on demand but not shift too much. We have to restore our attentional focus after falling victim to distraction. We have to modulate the depth and breadth of our attention. We need the ability for unfocused mindfulness. Each of these aspects of the attentional process is mediated by different neural circuitry.
Being better or worse at multitasking — dividing our attention — is only one of the ways to be better or worse at control of attention. For example, much of what passes for skill at sharing simultaneous attention among multiple tasks may really be skill at timeslicing, rapidly shifting. Or prioritizing the relative importance of foreground and background attention. Or balancing the focus and the unfocus.
Another factor in the stress imposed by multitasking may be not the challenge to neurocognitive control processes but to our self-presentation and self-integration. There are subtle or not-so-subtle influences to bring different personas to different tasks, especially when we interact remotely across electronic media. People have vastly different capacities to inhabit, balance and shift among different facets of their personality. At one extreme are those chameleonic individuals who reshape themselves in response to the demands of whatever context in which they find themselves; at the opposite extreme, those people who seem ‘themselves’ consistently across all contexts. The modulation and control of persona is, analogously, as complex and diverse as that of attention. The presentation of self in everyday life, to use Goffman’s term (1959), can either be comfortable or impose tremendous stress on the performer.