[extropy-chat] Fwd: Neural bottleneck limits multitasking?

Michael M. Butler mmbutler at gmail.com
Thu Jan 25 23:50:44 UTC 2007

Interesting if not utterly persuasive. I think there are modality
issues that I can't tell if this work addresses.

In particular, I'm not sure to what degree the example at top (cell
phone + driving) is more than a convenient article "hook".

What seems to be critical is the factoring of priorities so you don't
get "priority inversion" and other operating-system-like misbehaviors.
For instance,if the orbitofrontal cortex etc. has a clear notion/habit
that the phone conversation has lower priority than driving, what does
that do to the likelihood of a swapout at a bad moment?

One of the ironies of attention is: If everything matters, then nothing matters.

As paper authors like to say, "More research is needed."


via Eurekalert from Vanderbilt University


Neural bottleneck found that thwarts multi-tasking

Rene Marois and Paul Dux

Many people think they can safely drive while talking on their cell phones.
Vanderbilt neuroscientists Paul E. Dux and Rene Marois have found that when
it comes to handling two things at once, your brain, while fast, isn't that

"Why is it that with our incredibly complex and sophisticated brain, with
100 billion neurons processing information at rates of up to a thousand
times a second, we still have such a crippling inability to do two tasks at
once?" Marois, associate professor of Psychology, asked. "For example, what
is it about our brain that gives us such a hard time at being able to drive
and talk on a cell phone simultaneously?"

Researchers have long thought that a central "bottleneck" exists in the
brain that prevents us from doing two things at once. Dux and Marois are
the first to identify the regions of the brain responsible for this
bottleneck, by examining patterns of neural activity over time. Their
results were published in the Dec. 21 issue of Neuron.


The results revealed that the central bottleneck was caused by the
inability of the lateral frontal and prefrontal cortex, and also the
superior frontal cortex, to process the two tasks at once. Both areas have
been shown in previous experiments to play a critical role in cognitive
"We determined these brain regions responded to tasks irrespective of the
senses involved, they were engaged in selecting the appropriate response,
and, most importantly, they showed 'queing' of neural activity--the neural
response to the second task was postponed until the response to the first
was completed," Dux said.

"Neural activity seemed to be delayed for the second task when the two
tasks were presented nearly simultaneously - within 300 milliseconds of
each other," Marois said. "If individuals have a second or more between
tasks, we did not see this delay.

"This temporal delay is the essence of dual-task interference for tasks
that require actions. By using time-resolved fMRI, we can see its signature
in the brain," he continued. "These findings allow us to really now focus
on this set of brain areas and to understand why these areas cannot process
two tasks at once."

The researchers are interested in further exploring what is happening in
the bottleneck to slow performance and believe the work may have future
implications for people performing complex tasks.

"It may be possible to look to the sort of tasks people are going to have
to do in a very complex environment, such as flying a plane, and find out
under what circumstances these tasks may be less vulnerable to dual-task
interference," Dux added.


      Michael M. Butler  :  m m b u t l e r  ( a t )  g m a i l . c o m

'Piss off, you son of a bitch. Everything above where that plane hit
 is going to collapse, and it's going to take the whole building with it.
 I'm getting my people the fuck out of here."
   -- Rick Rescorla (R.I.P.), cell phone call, 9/11/2001

More information about the extropy-chat mailing list