Contagious Why Things Catch On

The nice thing about a wristband is that it lives on. The bike ride doesn’t. There’ll be pictures
of the bike ride and people will talk about the bike ride, but unless it goes on every year—
even if it does go on every year, it doesn’t live on as a reminder every day of this sort of stuff.
But the wristband does.
Behavioral residue is the physical traces or remnants that most actions or behaviors leave in their
wake. Mystery lovers have shelves full of mystery novels. Politicos frame photos of themselves
shaking hands with famous politicians. Runners have trophies, T-shirts, or medals from participating
in 5Ks.
As discussed in the chapter on Social Currency, items like the Livestrong wristband provide
insight into who people are and what they like. Even things that would otherwise be difficult to
observe, like whether a person donates to a particular cause or prefers mysteries to historical fiction.
But when publicly visible, these remnants facilitate imitation and provide chances for people to
talk about related products or ideas.
Take voting. It’s hard to get people to turn out to vote. They have to figure out where their polling
stations are located, take the morning off from work, and stand in line, sometimes for hours, until they
get the chance to cast their ballots. But these hurdles are compounded by the fact that voting is a
private act. Unless you actually happen to see all the people who go to the polls, you have no idea
how many other people decided voting was worth the effort. So there is not much social proof.
But in the 1980s election officials came up with a nice way to make voting more observable: the “I
Voted” sticker. Simple enough, but by creating behavioral residue, the sticker made the private act of
voting much more public, even after people left the polling station. It provided a ready reminder that
today is the day to vote, others are doing it, and you should too.
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Behavioral residue exists for all types of products and ideas. Tiffany, Victoria’s Secret, and a host
of other retailers give customers disposable shopping bags to carry their purchases home. But
because of the Social Currency associated with some of these retailers, many consumers reuse the
bags rather than tossing them. They use the Victoria’s Secret bags to carry their gym clothes, toss their
lunch into a Tiffany bag, or use Bloomingdale’s famous medium brown bag to carry papers around
town. People even reuse bags from restaurants, discount stores, and other places that are not status
symbols.

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Clothing retailer Lululemon takes this idea one step further. Rather than make paper bags that are
relatively durable, it makes shopping bags that are hard to throw away. Made of sturdy plastic like
reusable grocery bags, these bags are clearly meant to be reused. So people use them to carry
groceries or do other errands. But along the way this behavioral residue helps provide social proof
for the brand.
Giveaways can also provide behavioral residue. Go to any conference, job fair, or large meeting
where presenters have set up booths and you’ll be stunned by the amount of swag they give away.
Mugs, pens, and T-shirts. Beverage cozies, stress balls, and ice scrapers. A couple of years ago the
Wharton School even gave me a tie.
But some of these giveaways provide better behavioral residue than others. Giving away a makeup
carrying case is fine, but women usually apply makeup in the privacy of their bathrooms, so it doesn’t
make the brand that observable. Coffee mugs and gym bags might be used less frequently, but their use
is more publicly visible.
People posting their opinions and behavior online also provide behavioral residue. Reviews,
blogs, posts, or other sorts of content all leave evidence that others can find later. For this reason,
many businesses and organizations encourage people to Like them—or their content—on Facebook.
By simply clicking the Like button, people not only show their affinity with a product, idea, or
organization, they also help spread the word that something is good or worth paying attention to. ABC
News found that installing these buttons boosted its Facebook traffic by 250 percent.
Other sites push, or automatically post, what people do to their social networking pages. Music has
always been a somewhat social activity, but Spotify takes this a step further. The system allows you
to listen to whatever songs you like but also posts what you’re listening to on your Facebook page,
making it easier for your friends to see what you like (and letting them know about Spotify). Many
other websites do the same.
But should we always try to make things public? Are there ever instances when making something
public could be a bad idea?
ANTI-DRUG COMMERCIALS?
A sprightly, dark-haired teenager walks down the stairs of her apartment building. She’s wearing a
pretty silver necklace and carrying a sweater in her hand. She could be on her way to work or to meet
up with a friend for coffee. Suddenly a neighbor’s door opens and a voice whispers, “I got some good
pot for you.”
“No!” She scowls and hurries down the stairs.
A fresh-faced kid is sitting outside. He is wearing a blue sweatshirt and sports a bowl haircut that
used to be popular among boys. He appears deeply engrossed in a video game when a voice
interrupts him. “Cocaine?” the voice asks. “No thanks,” the kid replies.
A young man is standing against a wall chewing gum. “Yo, my man, want some ’ludes?” the voice
inquires. “No way!” the man exclaims, glaring back.
“Just Say No” is one of the most famous anti-drug campaigns of all time. Created by First Lady
Nancy Reagan during her husband’s presidency, the campaign ran public service announcements as
part of a national effort to discourage teens from recreational drug use in the 1980s and 1990s.
The logic was simple. One way or another, kids are going to be asked if they want to use drugs.
Whether by a friend, a stranger, or somebody else. And they needed to know how to say no. So the
government spent millions of dollars on anti-drug public service announcements. It hoped that the

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messages would teach kids how to react in these situations and, as a result, decrease drug use.
More recent campaigns have relied on the same idea. Between 1998 and 2004, Congress
appropriated almost $1 billion for the National Youth Anti-Drug Media Campaign. The goal was to
educate kids ages twelve to eighteen to enable them to reject drugs.
Communications professor Bob Hornik wanted to see whether anti-drug ads were actually
effective. So he collected data on the drug use of thousands of teens over the time the anti-drug ads
ran. Whether teens had seen the ads and whether they had ever smoked marijuana. Then he looked at
whether the public service announcements seemed to decrease marijuana use.
They didn’t.
In fact, the messages actually seemed to