The brain does some remarkable things when we aren’t paying attention. Consider how you engage tasks throughout the day. When you wake up in the morning, a script starts playing that runs you through task after task from the moment you step out of bed to the moment you get into your car on the way to work. You’re thinking as you hit all the steps in between, but you don’t have to think much about any of the steps themselves.
Managing that routine, however, takes considerable mental effort and focus. A specialized network of brain areas is making it happen—prompting us to remember (without actively remembering) all the details involved in getting ready for the day and executing them in a particular order while we’re already thinking about the details of two meetings, five deadlines and what’s for lunch.
This brain network, according to a new study, includes a medley of neurons in the front of the brain called the rostrolateral prefrontal cortex (RLPFC). Researchers from Brown University used fMRI to study the activity in several brain areas as people worked through sequences of unguided steps and found a unique “ramping up” pattern of activity in the RLPFC as the steps were engaged. When the sequence finished the RLPFC ramped back down, then immediately ramped up again as a new sequence started.
But neuroscientists aren’t content with merely linking a brain network to an ability, but are rather more interested in how they can trip it up. In this case they used transcranial magnetic stimulation (TMS)—a safe dose of magnetism that’s sort of like static moving through a phone line—to cause a brief blip in the brain network’s activity. By sending the TMS blip at different points throughout the sequence of steps, they were able to identify how the RLPFC directs our moment-to-moment behavior without requiring us to think much about it.
What it comes down to, according to lead researcher and postdoctoral fellow Theresa Desrochers, is “resolving uncertainty.” The RLPFC is essentially deciphering each step in the sequence like an inner supervisor determining what moves are needed to reach the objective. As the steps add up, the uncertainty factor increases, requiring more activity in the network of neurons to resolve.
"When we disrupt it we are disrupting that process of resolving the uncertainty," Desrochers said. "We therefore get this increasing pattern of errors because there was more uncertainty to be dealt with."
Much like the TMS pulse disrupting the supervisor’s focus, an overload on our attention can cause errors in this sophisticated, though seemingly routine, management of steps.
As Desrochers explained to me by email, “The study demonstrates that disrupting the brain’s supervisory system makes you more likely to commit an error. Exceeding our capacity, or having ‘a lot on your mind’ so to speak, could certainly overload our capacity to supervise and make us more vulnerable to such errors.”
Since the demands on our attention resources are ever-present, it’s interesting to consider how often we’re hitting our brains with the equivalent of TMS blips, and thus elevating the uncertainty factor. If you’re checking your email,
The takeaway: there's a lot of deciphering going on behind our daily routines, so cut your supervisor some slack.
The study was published in the journal Neuron.
You can find David DiSalvo on Twitter @neuronarrative and at his website daviddisalvo.org.
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