Bar-Ilan University
Summary:
Does your mind wander when
performing monotonous, repetitive tasks? Of course! But daydreaming involves
more than just beating back boredom. In fact, according to a new study, a
wandering mind can impart a distinct cognitive advantage.
Does your mind wander when
performing monotonous, repetitive tasks? Of course! But daydreaming involves
more than just beating back boredom. In fact, according to a new study
published in the Proceedings of the National Academy of Sciences, a wandering
mind can impart a distinct cognitive advantage.
Scientists at Bar-Ilan
University are the first to demonstrate how an external stimulus of low-level
electricity can literally change the way we think, producing a measurable
up-tick in the rate at which daydreams -- or spontaneous, self-directed
thoughts and associations -- occur. Along the way, they made another surprising
discovery: that while daydreams offer a welcome "mental escape" from
boring tasks, they also have a positive, simultaneous effect on task
performance.
The new study was carried out
in Bar-Ilan's Cognitive Neuroscience Laboratory supervised by Prof. Moshe Bar,
part of the University's Gonda (Goldschmied) Multidisciplinary Brain Research
Center which Prof. Bar also directs.
What Makes a Mind Wander?
While a far cry from the
diabolical manipulation of dream content envisioned in "Inception" --
the science-fiction thriller starring Leonardo DiCaprio -- the Bar-Ilan
University study is the first to prove that a generic external stimulus,
unrelated to sensory perception, triggers a specific type of cognitive
activity.
In the experiment -- designed
and executed by Prof. Bar's post-doctoral researcher Dr. Vadim Axelrod --
participants were treated with transcranial direct current stimulation (tDCS),
a non-invasive and painless procedure that uses low-level electricity to
stimulate specific brain regions. During treatment, the participants were asked
to track and respond to numerals flashed on a computer screen. They were also
periodically asked to respond to an on-screen "thought probe" in
which they reported -- on a scale of one to four -- the extent to which they
were experiencing spontaneous thoughts unrelated to the numeric task they had
been given.
The Brain-Daydream Connection
According to Prof. Bar -- a
long-time faculty member at Harvard Medical School who has authored several
studies exploring the link between associative thinking, memory and predictive
ability -- the specific brain area targeted for stimulation in this study was
anything but random.
"We focused tDCS
stimulation on the frontal lobes because this brain region has been previously
implicated in mind wandering, and also because is a central locus of the
executive control network that allows us to organize and plan for the
future," Bar explains, adding that he suspected that there might be a
connection between the two.
As a point of comparison and in
separate experiments, the researchers used tDCS to stimulate the occipital
cortex -- the visual processing center in the back of the brain. They also
conducted control studies where no tDCS was used.
While the self-reported
incidence of mind wandering was unchanged in the case of occipital and sham
stimulation, it rose considerably when this stimulation was applied to the
frontal lobes. "Our results go beyond what was achieved in earlier,
fMRI-based studies," Bar states. "They demonstrate that the frontal
lobes play a causal role in the production of mind wandering behavior."
Improved "Cognitive
Capacity" of the Wandering Mind
In an unanticipated finding,
the present study demonstrated how the increased mind wandering behavior
produced by external stimulation not only does not harm subjects' ability to
succeed at an appointed task, it actually helps. Bar believes that this surprising
result might stem from the convergence, within a single brain region, of both
the "thought controlling" mechanisms of executive function and the
"thought freeing" activity of spontaneous, self-directed daydreams.
"Over the last 15 or 20
years, scientists have shown that -- unlike the localized neural activity
associated with specific tasks -- mind wandering involves the activation of a
gigantic default network involving many parts of the brain," Bar says.
"This cross-brain involvement may be involved in behavioral outcomes such
as creativity and mood, and may also contribute to the ability to stay
successfully on-task while the mind goes off on its merry mental way."
While it is commonly assumed
that people have a finite cognitive capacity for paying attention, Bar says
that the present study suggests that the truth may be more complicated.
"Interestingly, while our
study's external stimulation increased the incidence of mind wandering, rather
than reducing the subjects' ability to complete the task, it caused task
performance to become slightly improved. The external stimulation actually
enhanced the subjects' cognitive capacity."
Toward A Less-Mysterious Mind
Bar says that, in the future,
he would be interested in studying how external stimulation might affect other
cognitive behaviors, such as the ability to focus or perform multiple tasks in
parallel. And while any therapeutic application of this technique is
speculative at best, he believes that it might someday help neuroscientists
understand the behavior of people suffering from low or abnormal neural
activity.
In the meantime, Bar's team at
the BIU Lab for Cognitive Neuroscience is pleased to note that in their work on
mind wandering -- probably the most omnipresent internal cognitive function --
they have made the human brain just a little less mysterious
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Story Source:
The above story is based on
materials provided by Bar-Ilan University. Note: Materials may be edited for
content and length.
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Journal Reference:
1. Vadim Axelrod, Geraint Rees, Michal Lavidor, Moshe Bar.
Increasing propensity to mind-wander with transcranial direct current
stimulation. Proceedings of the National Academy of Sciences, 2015; 201421435 DOI:
10.1073/pnas.1421435112
