  "Media events" such as political debates generate conditions of shared
attention as many users simultaneously tune in with the dual screens of
broadcast and social media to view and participate. Are collective patterns of
user behavior under conditions of shared attention distinct from other "bursts"
of activity like breaking news events? Using data from a population of
approximately 200,000 politically-active Twitter users, we compare features of
their behavior during eight major events during the 2012 U.S. presidential
election to examine (1) the impact of "media events" have on patterns of social
media use compared to "typical" time and (2) whether changes during media
events are attributable to changes in behavior across the entire population or
an artifact of changes in elite users' behavior. Our findings suggest that
while this population became more active during media events, this additional
activity reflects concentrated attention to a handful of users, hashtags, and
tweets. Our work is the first study on distinguishing patterns of large-scale
social behavior under condition of uncertainty and shared attention, suggesting
new ways of mining information from social media to support collective
sensemaking following major events.
