Contagious: Why Things Catch On - by Jonah Berger


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One of my favorite books of all time. This is one of those books that you shouldn't hesitate to read more than once to absorb as much as you can.

Recommendation: 5/5

My Highlights

One reason some products and ideas become popular is that they are just plain better. We tend to prefer websites that are easier to use, drugs that are more effective, and scientific theories that are true rather than false. So when something comes along that offers better functionality or does a better job, people tend to switch to it.

Another reason products catch on is attractive pricing. Not surprisingly, most people prefer paying less rather than more. So if two very similar products are competing, the cheaper one often wins out. Or if a company cuts its prices in half, that tends to help sales.

...although quality, price, and advertising contribute to products and ideas being successful, they don't explain the whole story.

Social influence and word of mouth. People love to share stories, news, and information with those around them.

The things others tell us, e-mail us, and text us have a significant impact on what we think, read, buy, and do.

Word of mouth is the primary factor behind 20 percent to 50 percent of all purchasing decisions.

Consequently, social influence has a huge impact on whether products, ideas, and behaviors catch on.

Word of mouth is more effective than traditional advertising for two key reasons. First, it's more persuasive.

Their objectivity, coupled with their candidness, make us much more likely to trust, listen to, and believe our friends.

Second, word of mouth is more targeted

Word of mouth, on the other hand, is naturally directed toward an interested audience. We don't share a news story or recommendation with everyone we know. Rather, we tend to select particular people who we think would find that given piece of information most relevant.

A particularly nice example of how word of mouth improves targeting came to me in the mail a few years ago. Every so often publishers will send me free books. But a few years ago, one company did something slightly different. It sent me two copies of the same book. They sent a note explaining why they thought the book would be good for my students, but they also mentioned that they sen a second copy so that I could pass it along to a colleague who might be interested.

That's how word of mouth helps with targeting. Rather than sending books to everyone, the publishers got me, and others, to do the targeting for them. Just like a searchlight, each recipient of the double mailing would look through his or her personal social network, find the person that the book would be most relevant for, and pass it along.

Six key STEPPS...that cause things to be talked about, shared, and imitated.

Principle 1: Social Currency

How does it make people look to talk about a product or idea?

Principle 2: Triggers

How do we remind people to talk about our products and ideas?

Principle 3: Emotion

When we care, we share.

Principle 4: Public

Can people see when other are using our product or engaging in our desired behavior?

Principle 5: Practical Value

How can we craft content that seems useful?

Principle 6: Stories

What broader narrative can we wrap our idea in? People don't just share information, they tell stories.

...the six principles of contagiousness: product or ideas that contain Social Currency and are Triggered, Emotional, Public, Practically Valuable, and wrapped into Stories.

As it turns out, if something is supposed to be secret, people might well be more likely to talk about it. The reason? Social currency. People share things that make them look good to others.

"Self-sharing" follows us throughout our lives. We tell friends about our new clothing purchases and show family members the op-ed piece we're sending to the local newspaper. This desire to share our thoughts, opinions, and experiences is one reason social media and online social networks have become so popular.

What people talk about also affects what others think of them.

...people prefer sharing things that make them seem entertaining rather than boring, clever rather than dumb, and hip rather dull.

So to get people talking, companies and organizations need to mint social currency. Give people a way to make themselves look good while promoting their products and ideas along the way. There are three ways to do that: (1) find inner remarkability; (2) leverage game mechanics; and (3) make people feel like insiders.

...talking about remarkable things provides social currency.

...remarkable things get brought up more often.

Emphasize what's remarkable about a product or idea and people will talk.

Game mechanics are the elements of a game, application, or program—including rules and feedback loops—that make them fun and compelling.

Good game mechanics keep people engaged, motivated, and always wanting more. mechanics also motivate us on an interpersonal level by encouraging social comparison.

People don't just care about how they are doing, they care about their performance in relation to others.

Scarcity is about how much of something is offered. Scarce things are less available because of high demand, limited production, or restrictions on the time or place you can acquire them.

Exclusivity is also about availability, but in a different way. Exclusive things are accessible only to people who meet particular criteria.

...exclusivity isn't just about money or celebrity. It's also about knowledge. Know certain information or being connected to people who do.

Scarcity and exclusivity help products catch on by making them seem more desirable. If something is difficult to obtain, people assume that it must be worth the effort. If something is unavailable or sold out, people often infer that lots of other people must like it, and so it must be pretty good...

Scarcity and exclusivity boost word of mouth by making people feel like insiders. If people get something not everyone else has, it makes them feel special, unique, high status. And because of that they'll not only like a product or service more, but tell other about it. Why? Because telling other makes them look good. Having insider knowledge is social currency.

The mere fact that something isn't readily available can make people value it more and tell other to capitalize on the social currency of knowing about it or having it.

Some word of mouth is immediate, while some is ongoing.

...immediate word of mouth. This occurs when you pass on the details of an experience, or share new information you've acquired, soon after it occurs.

Ongoing word of mouth, in contrast, cover the conversations you have in the weeks and months that follow.

Both types of word of mouth are valuable, but certain types are more important for certain products or ideas.

Top of mind means tip of tongue.

...a strong trigger can be much more effective than a catchy slogan.

Triggers explain why. Even a bad review or negative word of mouth can increase sales if it informs or reminds people that the product or idea exists.

Even negative attention can be useful if it makes products and ideas top of mind.

Products and ideas also have habitats, or sets of triggers that cause people to think about them.

Most products or ideas have number of natural triggers.'s also possible to grow an idea's habitat by creating new links to stimuli in the environment.

Competitors can even be used as a trigger.

...transform a weakness into a strength: by making a rival's message act as a trigger for your own.

Researchers call this strategy the poison parasite because it slyly injects "poison" (your message) into a rival's message by making it a trigger for your own.

Triggers can help products and ideas catch on, but some stimuli are better triggers than others. key factor is how frequently the stimulus occurs.

It is also important to pick triggers that happen near where the desired behavior is taking place.

The more something is triggered, the more it will be top of mind, and the more successful it will become.

...most-share lists have a powerful ability to shape public discourse.

For something to go viral, lots of people have to pass along the same piece of content at around the same time.

...sharing useful information helps others and makes the sharer look good in the process.

...positive articles were more likely to be highly shared than negative ones.

When inspired by awe we can't help wanting to tell people what happened. Other emotions, however, have the opposite effect: they stifle action. Take sadness...Contentment also deactivates.

...awe increased sharing and that sadness decreased it.

...some negative emotions, like anger or anxiety, actually increased sharing.

Anger and anxiety lead people to share because, like awe, they are high-arousal emotions.

Arousal is also one reason funny things get shared.

...amusement is a high-arousal emotion.

When trying to use emotions to drive sharing, remember to pick ones that kindle the fire: select high-arousal emotions that drive people to action. On the positive side, excite people or inspire them by showing them how they can make a difference. On the negative side, make people mad, not sad. Make sure the polar bear story gets them fired up.

Simply adding more arousal to a story or ad can have a big impact on people's willingness to share it.

Negative emotions can also drive people to talk and share.

Emotions drive people to action.

If it's hard to see what others are doing, it's hard to imitate it. Making something more observable makes it easier to imitate it. Making something more observable makes it easier to imitate. Thus a key factor in driving products to catch on is public visibility. If something is built to show, it's built to grow.

Social proof. People assume that the longer the line, the better the food must be.

...behavior is public and thoughts are private.

"Monkey see, monkey do"

People can imitate only when they can see what others are doing.

Observability has huge impact on whether products and ideas catch on.

Public visibility boosts word of mouth.

One way to make things more public is to design ideas that advertise themselves.

Designing products that advertise themselves is a particularly powerful strategy for small companies or organizations that don't have a lot of resources.

A product, idea, or behavior advertises itself when people consume it.

Is there something that generates social proof that sticks around even when the product is not being used or the idea is not top of mind? Yes. And it's called behavioral residue.

LiveStrong wristbands as behavioral residue.

People like to pass along practical, useful information. News others can use.

Passing along useful things also strengthens social bonds.

...the size of the discount influences how good a deal seems.

The way people actually make decisions often violates standard economic assumptions about how they should make decisions. Judgements and decisions are not always rational or optimal. Instead, they are based on psychological principles of how people perceive and process information. Just as perceptual processes influence whether we see a particular sweater as red or view an object on the horizon as far away, they also influence whether a price seems high or a deal seems good.

One of the main tenets of prospect theory is that people don't evaluate things in absolute terms. They evaluate them relative to a comparison standard, or "reference point."

...using the word "sale" beside a price increased sales even though the price itself stayed the same.

Another tenet of prospect theory is something called "diminishing sensitivity."

Diminishing sensitivity reflects the idea that the same change has a smaller impact the farther it is from the reference point.

Deals seem more appealing when they highlight incredible value.

Another factor that affects whether deals seem valuable is their availability.

...making promotions more restrictive can actually make them more effective.

...restricting availability through scarcity and exclusivity makes things seem more valuable.

Putting something on sale can make it seem like a good deal. But if a product is always on sale people start to adjust their expectations.

...offers that are available for only a limited time seem more appealing because of the restriction. Quantity limits work the same way.

...quantity purchase limits increase sales by more than 50 percent.

Even restricting who has access can make a promotional offer seem better.

The Rule of 100

Another framing factor that impacts practical value is how promotional offers are expressed.

Researchers find that whether a discount seems larger as money or percentage off depends on the original price. For low-priced products, like books or groceries, price reductions seem more significant when they are framed in percentage terms.

For high-priced products, however, the opposite is true.

...framing price reductions in dollar terms (rather than percentage terms) makes them seem like a better offer.

A simple way to figure out which discount frame seems larger is by using something called the Rule of 100.

If the product's price is less than $100, the Rule of 100 says that percentage discounts will seem larger. For a $30 T-shirt or a $15 entree, even a $3 discount is still a relatively small number. But percentagewise (10 percent or 20 percent), that same discount looks much bigger.

If the product's price is more than $100, the opposite is true. Numerical discounts will seem larger. Take a $750 vacation package or the $2,000 laptop. While a 10 percent discount may seem like a relatively small number, it immediately seems much bigger when translated into dollars ($75 or $200).

...practical value is more effective the easier it is for people to see.

...content that is obviously relevant to a narrow audience may actually be more viral.

...people don't think in terms of information. They think in terms of narratives.

Stories are the original form of entertainment.

Narratives are inherently more engrossing than basic facts. They have a beginning, middle, and end. If people get sucked in early, they'll stay for the conclusion.

Stories...provide a quick and easy way for people to acquire lots of knowledge in a vivid and engaging fashion.

People are also less likely to argue against stories than against advertising claims.

Stories thus give people an easy way to talk about products and ideas.


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