REMINISCING CAN HELP BOOST MENTAL PERFORMANCE
To solve a mental
puzzle, the brain’s executive control network for externally focused,
goal-oriented thinking must activate, while the network for internally directed
thinking like daydreaming must be turned down to avoid interference – or so we
thought.
New research led by
Cornell University neuroscientist Nathan Spreng shows for the first time that
engaging brain areas linked to so-called “off-task” mental activities (such as
mind-wandering and reminiscing) can actually boost performance on some challenging
mental tasks. The results advance our understanding of how externally and
internally focused neural networks interact to facilitate complex thought, the
authors say.
“The prevailing view
is that activating brain regions referred to as the default network impairs
performance on attention-demanding tasks because this network is associated
with behaviors such as mind-wandering,” said Spreng. “Our study is the first to
demonstrate the opposite – that engaging the default network can also improve
performance.”
There are plenty of
neuroimaging studies showing that default network activation interferes with
complex mental tasks – but in most, Spreng explained, the mental processes
associated with default network conflict with task goals. If you start thinking
about what you did last weekend while taking notes during a lecture, for
example, your note-taking and ability to keep up will suffer.
Spreng and his team
developed a new approach in which off-task processes such as reminiscing can
support rather than conflict with the aims of the experimental task. Their
novel task, “famous faces n-back,” tests whether accessing long-term memory
about famous people, which typically engages default network brain regions, can
support short-term memory performance, which typically engages executive
control regions.
While undergoing brain
scanning, 36 young adults viewed sets of famous and anonymous faces in sequence
and were asked to identify whether the current face matched the one presented
two faces back. The team found participants were faster and more accurate when
matching famous faces than when matching anonymous faces and that this better
short-term memory performance was associated with greater activity in the
default network. The results show that activity in the default brain regions
can support performance on goal-directed tasks when task demands align with
processes supported by the default network, the authors say.
“Outside the
laboratory, pursuing goals involves processing information filled with personal
meaning – knowledge about past experiences, motivations, future plans and
social context,” Spreng said. “Our study suggests that the default network and
executive control networks dynamically interact to facilitate an ongoing
dialogue between the pursuit of external goals and internal meaning.”
The study,
“Goal-congruent default network activity facilitates cognitive control,”
published in October in the Journal of Neuroscience, was funded in
part by the National Institutes of Health and the Natural Sciences and Engineering
Research Council of Canada.
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