The lemming factor

We are strongly influenced by what others do.

Felix Reed-Tsochas of Oxford University's Saïd Business School and Jukka-Pekka Onnela from Harvard University decided to study how users of Facebook use "apps," the little thingies that add to the experience.

The Economist reports:

They pored over (anonymous) data of the entire Facebook population in July and August 2007 (around 50m at the time), and at all but a few of the 2720 apps available for download in the same period. This amounted to a total of some 104m app installations. At that time, a Facebook user's apps were all visible to friends, who were also notified when any new app was downloaded (a practice Facebook has since abandoned). This, along with a display of the total number of installations of each app, were the only ways apps were plugged, permitting the researchers to control for the effects of external advertising. Any effects observed would thus be wholly attributable to social influence, not canny ad men.

Dr Reed-Tsochas and Dr Onnela duly discovered that the social networkers' herd mentality was intact, with popular apps doing best, and the trendiest reaching stratospheric levels. A typical app was installed around 1,000 times, but the highest-ranked notched up an astonishing 12m users. What did come as something of a surprise, though, was that our inner lemming only kicked in once the app had breached a clear threshold rate of about 55 installations a day. Any fewer than that and users seemed oblivious to their friends' preferences. Interestingly, after some serious number crunching, the researchers found that this cannot be put down purely to the network effect, ie, the idea that adopting a certain innovation only makes sense if enough other people have done so. Indeed, this effect appeared less pronounced than might have been expected.

Dr Reed-Tsochas and Dr Onnela suggest that two discrete behavioural patterns emerged. Users appeared to treat any app with more than 55 daily installations differently to those with fewer downloads. Under 55 daily installations, friend behaviour was an instrumental part of the decision to install. Over 55 daily installations, and friend behaviour didn't matter one jot. Virtual lemmings are, it seems, discriminating in ways we still don't quite comprehend. As is, no doubt, the offline troop.

Monkey see, monkey do.