news event. In this situation, almost all of the activity comes after the
initial peak. The third type of popularity occurs when a video is being
shared elsewhere online, gradually accumulating views before
peaking and declining again. It’s also possible to observe a mixture of
these shapes; a shared video may get a boost by being featured then
settle back down to a low level, like mine did.[66]
Video is a particularly persistent form of media, with interest
tending to last much longer than for news articles. A typical social
media news cycle is around two days; in the first twenty-four hours,
most content comes in the form of articles, with shares and
comments following afterwards.[67] However, not all news is the
same. Researchers at MIT have found that false news tends to
spread further and faster than true news. Maybe this is because high-
profile people with lots of followers are more likely to spread
falsehoods? The researchers actually found the opposite: it was
generally people with fewer followers who spread the false news. If
we think of contagion in terms of the four DOTS, this suggests false
information spreads because the transmission probability is high,
rather than there being more opportunities for spread. The reason for
the high transmission probability? Novelty might have something to
do with it: people like to share information that’s new, and false news
is generally more novel than true news.[68]
It’s not just about novelty, though. To understand how things
spread online, we also need to think about social reinforcement. And
that means taking another look at the concept of complex contagion:
sometimes we need to be exposed to an idea multiple times before
we adopt it online. For example, there’s evidence that we’ll share
memes online without much prompting, but won’t share political
content until we see several other people doing so. When Facebook
users changed their profile picture to a ‘=’ symbol in support of
marriage equality in early 2013, on average they only did so once
eight of their friends had. Complex contagion also influenced the
initial adoption of many online platforms, including Facebook, Twitter
and Skype.[69]
A quirk of complex contagion is that it spreads best in tight-knit
communities. If people share lots of friends, it creates the multiple