The Science of Social (Media)
Influence
Sinan Aral @sinanaral
Initiative on the Digital Economy
April 4,1 2014
Massachusetts Institute of Technology
MIT Sloan School of Management
@sinanaral
Explosion of Digital ‘Social Signals’
From Peers and ‘The Crowd’
Initiative on the Digital Economy
Massachusetts Institute of Technology
MIT Sloan School of Management
@sinanaral
@sinanaral
@sinanaral
Initiative on the Digital Economy
Massachusetts Institute of Technology
MIT Sloan School of Management
@sinanaral
Causal Inference
Initiative on the Digital Economy
Massachusetts Institute of Technology
MIT Sloan School of Management
@sinanaral
Source: Bloomberg.com
@sinanaral
Source: Bloomberg.com
@sinanaral
Source: Bloomberg.com
The “Reflection Problem”
@sinanaral
Human behaviors cluster in
network space and time…
but is this because of
peer influence or
alternate explanations?
Initiative on the Digital Economy
Massachusetts Institute of Technology
MIT Sloan School of Management
@sinanaral
“If you see a crowd of people all put up their umbrellas at the
same time, you don’t assume that social influence is responsible.”
– Max Weber

Global IM Network of 27 Million Users
from Yahoo! (Daily Traffic)

Detailed demographics and
geographic data.

Comprehensive, detailed and precise
data on online behaviors/activities.

Day by Day adoption and usage of a mobile service application
(Yahoo Go) launched in July 2007. (532,365 Adopters)
12500
1
0.9
Dot Product
Adopters per day
10000
7500
5000
2500
0
Jul 1
Aug 1
Sep 1
Oct 1
Nov 1
0.8
0.7
Jul 1
Time
dTshuffled)
s
0.06
Aral, Muchnik & Sundararajan (2009)
“Distinguishing Influence Based Contagion from
2
0.05
Homophily Driven Diffusion in Dynamic
Networks,” PNAS, December.
@sinanaral
P(Adoption | Friend Adopts)
16
14
INFLUENCE
12
Controlling for correlated preferences
and confounding effects
10
8
6
4
2
0
20
40
60
80
100
120
140
160
DAYS SINCE LAUNCH
Initiative on the Digital Economy
Massachusetts Institute of Technology
MIT Sloan School of Management
@sinanaral
“VIRAL DESIGN” Can we engineer products so
they are more likely to be virally shared?
Aral & Walker (2011) “Creating Social Contagion through Viral Product Design: A
Randomized Trial of Influence in Networks,” Management Science, September.
@sinanaral
The Setup
App
 Randomly Enabled Viral Messaging.
 Observed the Adoption and Use of the App by Friends of
Control and Experimental Group Users.
Initiative on the Digital Economy
Massachusetts Institute of Technology
MIT Sloan School of Management
@sinanaral
Which Features Spread Contagion Best?
Personal
Invitations
Influence Per
Message
Global Diffusion
Stickiness
↑6%
Passive
Awareness
↑2%
↑98% ↑246%
↑17%
0%
@sinanaral
@sinanaral
@sinanaral
Experiment 2
We Randomized
Receipt of Notifications
Only a Randomly Selected
Subset of Neighbors
Receive Passive Viral
Messages
Allows us to test:
Randomized Trails o
Influence and
Susceptibility to
Influence
Initiative on the Digital Economy
Massachusetts Institute of Technology
MIT Sloan School of Management
@sinanaral
Susceptibility to Influence
2
1,9
1,8
1,7
1,6
1,5
1,4
1,3
1,2
1,1
1
Single
Relationship
Engaged
Married
Its
Complicated
Initiative on the Digital Economy
Massachusetts Institute of Technology
MIT Sloan School of Management
Patterns of Influence in Network Data
@sinanaral
My Experience Rating DOJO on Yelp…
@sinanaral
Social Influence Bias
25% ↑ in Mean
Ratings
Muchnik, L., Aral, S., Taylor, S. (2013) “Social Influence Initiative on the Digital Economy
Massachusetts Institute of Technology
Bias: A Randomized Experiment.” Science, August.
MIT Sloan School of Management
@sinanaral
A “Superstar” Effect
Positive herding snowballs
into “Ratings Stardom.”
30% more likely to exceed
a score of 10
Mean rating = 1.9
Negative herding is
neutralized by the
correction effect.
@sinanaral
Implications
 Encourage positive customers to rate early.
 Does fraud prevention work?
 What does herding mean for sales, stock prices,
prediction markets?
 Do polls predict or drive election results?
Initiative on the Digital Economy
Massachusetts Institute of Technology
MIT Sloan School of Management
Personalized Social Advertising
(A 250M Person Experiment)
Facebook “Social Ads”
@sinanaral
Initiative on the Digital Economy
Massachusetts Institute of Technology
MIT Sloan School of Management
@sinanaral
@sinanaral
@sinanaral
Thank You!
Sinan Aral @sinanaral
Initiative on the Digital Economy
April 4,
322014
Massachusetts Institute of Technology
MIT Sloan School of Management