Fascinating observations by Jimenez et al. on our inherent human drive to understand our vastly social world...(and in the same issue of PNAS note this study on the importance of the social presence of either human or virtual instructors in multimedia instructional videos.)
Significance
Writer
Kurt Vonnegut once said “if you describe a landscape or a seascape, or a
cityscape, always be sure to include a human figure somewhere in the
scene. Why? Because readers are human beings, mostly interested in other
human beings.” Consistent with Vonnegut’s intuition, we found that the
human brain prioritizes learning scenes including people, more so than
scenes without people. Specifically, as soon as participants rested
after viewing scenes with and without people, the dorsomedial prefrontal
cortex of the brain’s default network immediately repeated the scenes
with people during rest to promote social memory. The results add
insight into the human bias to process the social landscape.
Abstract
Sociality
is a defining feature of the human experience: We rely on others to
ensure survival and cooperate in complex social networks to thrive. Are
there brain mechanisms that help ensure we quickly learn about our
social world to optimally navigate it? We tested whether portions of the
brain’s default network engage “by default” to quickly prioritize
social learning during the memory consolidation process. To test this
possibility, participants underwent functional MRI (fMRI) while viewing
scenes from the documentary film,
Samsara. This film shows
footage of real people and places from around the world. We normed the
footage to select scenes that differed along the dimension of sociality,
while matched on valence, arousal, interestingness, and familiarity.
During fMRI, participants watched the “social” and “nonsocial” scenes,
completed a rest scan, and a surprise recognition memory test.
Participants showed superior social (vs. nonsocial) memory performance,
and the social memory advantage was associated with neural pattern
reinstatement during rest in the dorsomedial prefrontal cortex (DMPFC), a
key node of the default network. Moreover, it was during early rest
that DMPFC social pattern reinstatement was greatest and predicted
subsequent social memory performance most strongly, consistent with the
“prioritization” account. Results simultaneously update 1) theories of
memory consolidation, which have not addressed how social information
may be prioritized in the learning process, and 2) understanding of
default network function, which remains to be fully characterized. More
broadly, the results underscore the inherent human drive to understand
our vastly social world.