still not have been feasible to ask for consent beforehand. In his book
Bit by Bit, sociologist Matthew Salganik points out that psychological
experiments can produce dubious results if people know what’s being
studied. Participants in the Facebook study might have behaved
differently if they had known from the outset that the research was
about emotions. If psychology researchers do deceive participants in
order to get a natural reaction, however, Salganik notes that they will
often debrief them afterwards.
As well as debating the ethics of the experiment, the wider
research community also raised concerns about the extent of
emotional contagion in the Facebook study. Not because it was big,
but because it was so small. The experiment had shown that when a
user saw fewer positive posts in their feed, the number of positive
words in their status updates fell by an average of 0.1 per cent.
Likewise, when there were fewer negative posts, negative words
decreased by 0.07 per cent.
One of the quirks of huge studies is that they can flag up very
small effects, which wouldn’t be detectable in smaller studies.
Because the Facebook study involved so many users, it was possible
to identify incredibly small changes in behaviour. The study team
argued that such differences were still relevant, given the size of the
social network: ‘In early 2013, this would have corresponded to
hundreds of thousands of emotion expressions in status updates per
day.’ But some people remained unconvinced. ‘Even if you were to
accept this argument,’ Salganik wrote, ‘it is still not clear if an effect of
this size is important regarding the more general scientific question
about the spread of emotions.’
I , social media companies have a major
advantage because they can monitor much more of the transmission
process. In the Facebook emotion experiment, the researchers knew
who had posted what, who had seen it, and what the effect was.
External marketing companies don’t have this same level of access,
so instead they have to rely on alternative measurements to estimate
the popularity of an idea. For example, they might track how many