How to achieve influence: Cognitive behaviour

Sarah Macdonald and Tom Ewing

Influence is more likely to come from irrational, emotional cues than from rational evaluation of what advocates are saying, and is often sought to justify a decision post-event.

Common-sense ideas of influence paint us as a species of information seekers and spreaders, and assume we evaluate information and its sources before making decisions.

Like a winning meme, this common-sense, information-based model of influence is both persuasive and successful. Popular theories of how it works – from Malcolm Gladwell's The Tipping Point to Duncan Watts' 'many fires' -have been followed by practical contributions from researchers trying to turn them into data that marketers can use.

But, unfortunately, 'influence' is a slippery concept, with an annoying habit of revealing its complexities just as you think you've got it nailed. For instance, a 2009 study conducted by TNS found that separating a population into 'influential' and 'influenced' by claimed attitudes was no easy task: many participants were both, some claimed to be neither. Meanwhile, social media has given us a magnificent, billions-strong laboratory to study how behaviour cascades and spreads, and forced us to concede that easy answers are in short supply.