Michal Kosinski is an assistant
professor of organizational behavior
at Stanford GSB.
Silicon Valley and Washington are both in
an uproar about revelations that Cambridge
Analytica, a pro-Trump “psychographic”
consulting firm, got ahold of detailed
personal data on 87 million Facebook users.
But while much of the furor has been
over privacy and ethics, a practical question
remains: Is psychological targeting an
effective tool of digital propaganda?
The answer, according to a Stanford
researcher who pioneered many of the
original techniques, is “yes.”
“I’ve been warning about these risks for
years,” says Michal Kosinski, a psychologist
and assistant professor of organizational
behavior at Stanford GSB. “Our latest research
confirms that this kind of psychological
targeting is not only possible but effective as
a tool of digital mass persuasion.”
(Note: Kosinski never worked for
Cambridge Analytica and never acquired
Facebook data without users’ permission.)
TAKING ADVANTAGE OF
As a doctoral student and deputy director at
Cambridge University Psychometrics Center
from 2008 to 2014, Kosinski worked with
a colleague to investigate whether it was
possible to identify people’s psychological
traits from their Facebook “likes.”
People who liked Battlestar Galactica
were likely to be introverts, for example, while
people who liked Lady Gaga were likely to
be extroverts. Kosinski and his Cambridge
colleague, David Stillwell, were able to
correlate likes with other basic personality
traits: openness, conscientiousness,
agreeableness, and neuroticism. Armed with
only 10 likes, they could evaluate a person’s
traits more accurately than that person’s
coworkers. With 70 likes, they could do better
than a person’s close friends.
And now, in a new study, Kosinski and
his colleagues — including Stillwell, Sandra
Matz of Columbia Business School, and
Gideon Nave of Wharton School of Business
— confirm the next logical step: Ads are
indeed more persuasive when they
are tailored to those psychological traits.
RESEARCH MEANT TO WARN
Kosinski isn’t boasting about this.
“Most of my studies have been intended
as warnings,” he says. “You can imagine
applications that are for the good, but it’s
much easier to think of applications that
manipulate people into decisions
that are against their own interests.”
He and his colleagues created
a Facebook app that allowed people to
fill out a personality questionnaire that
measures five basic personality traits.
They then asked users for access to their
likes, eventually amassing a database
with 3 million profiles.
By correlating people’s likes with their
scores on the personality questionnaire,
Kosinski and Stillwell developed algorithms
to accurately infer a host of personality
traits from a person’s Facebook activity.
The founders of Cambridge Analytica
adopted similar techniques and applied them
to politics. They also went a big step further,
using their own app to secretly collect the
Facebook activity on tens of millions of users
who had simply been friends of people who
had taken the app’s quiz.
MEASURING THE EFFECT OF
In their new study, Kosinski and his
colleagues wanted to see if psychological
targeting actually delivered better results
in advertising. The researchers ran three
experimental ad campaigns over Facebook.
In promoting a line of cosmetics, for
example, they ran dueling ads aimed at
introverts and extroverts. All told, the ads
reached 3 million people.
The ad for extroverts featured a woman
dancing and the slogan “Dance like no one’s
watching (but they totally are).” By contrast,
the ad for introverts featured a woman
contemplating herself in a mirror and a quiet
slogan: “Beauty doesn’t have to shout.”
Sure enough, people were 50% more likely
to buy the cosmetics if they saw the ad aimed
at their particular type.
The results were similar when the
researchers promoted a crossword puzzle app
for smartphones with ads that targeted users
based on their openness to new things.
People who had been identified as very
open were urged to “unleash your creativity”
on “an unlimited number” of puzzles. People
identified as likely to cling to the familiar were
told to “settle in with an all-time favorite.”
Those who saw the ad aimed at their
particular level of openness were 30% more
likely to download the game than those
In a third test, Kosinski and his colleagues
tested rival ads for a video game that they
already knew appealed heavily to introverts.
The first ad featured a standard action-
packed pitch: “Ready? Fire! ...” The second
ad was tailored to introverts: “Phew! Hard
day? How about a puzzle to wind down with?”
Here, the ads for introverts generated 30%
more clicks and 20% more downloads.
Kosinski says it’s probably impossible to
prohibit psychological targeting as a tool of
political propaganda, but he says people can
defend themselves by becoming aware of
how it works. They may also be able to enact
policies that prevent abuses.
“It’s a bit like fire,” he says. “You can
use fire to both warm your house and burn
it down. You can’t ban fire, and you can’t
stop some people from committing arson.
What you need are firefighters and fire-safety equipment.” Δ
A new study shows that psychological
profiling on social media not only works for
advertisers — it works very well.
BY EDMUND L. ANDREWS
Illustration by Daniel Stolle