Evil by Design

Chris Nodder
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A collection of design patterns that aim to exploit human frailties and "make users emotionally involved in doing something that benefits the designer more than them." Each chapter deals with one of the Seven Deadly Sins (Gluttony, Pride, Sloth, and so on).


To prevent buyer’s remorse, get customers to imagine the experiences they’ll have with your product or the way that others will react when they see the customer using your product.

If more people are doing something, it lends additional credibility to the activity.

  • After you sign up to Google+ and add some people to your own circles, you perpetuate the social proof effect. In addition, when you reciprocate with an “add,” Google informs the person who first added you that “they want to hear from you.”
  • Even more insidious is LinkedIn and Facebook’s habit of using your name and likeness in ads seen by your friends and contacts saying that YOU recommended/used/did this thing, so your contacts should, too. An e-mail from LinkedIn uses my connections’ names and likenesses to convince me to do something. If all of these respectable professionals are doing it, maybe I should be too.
  • Most individuals—even when told about Social Proof—claim that other people’s behavior doesn’t influence their own.

Commitment to a goal is much more concrete if the commitment is written down.

B.J. Fogg, founder of the Stanford Persuasive Technology Lab, lists four elements to website credibility. They are: presumed credibility (assumptions made by the user), surface credibility (first impressions of the site), reputed credibility (third-party endorsements), and earned credibility (built over time).

Pander to people’s desire for order.

  • LinkedIn uses language that makes it clear that you are currently in a disorderly state. Claiming “your profile is 25% complete” creates enough disharmony to convince people to hand over their e-mail address book, add more connections, and start recommending others in the network.
  • People don’t like being forced to consider two competing ideas because that keeps them out of the state of closure that they desire.


Thinking of sloth as avoiding work or not caring about outcomes gives us a useful perspective; namely that people are not motivated to do more than the absolute minimum work to achieve their online aims.

The easiest way to get people to your desired outcome is to ensure it follows the path of least resistance.

  • Provide fewer options The more items, the more likelihood of procrastination.
  • When you want to increase the perceived importance of making the decision, allow users to choose between multiple similar options (all with positive outcomes for you). The longer they spend in this illusion of choosing, the more importance they will attribute to the resulting decision (and the more they’ll be wedded to it).
  • Recommendation engines are a great way to limit choice from an otherwise overwhelming quantity of items. (Netflix.com)

Priming: If they show you specific words or pictures beforehand, you’ll find it easier to recall those items or related ones in a later test, even after you have consciously forgotten the specific words.

The harder it is to cancel the membership, the more people’s slothful behavior will kick in.


The average restaurant meal in the United States is four times larger now than it was in the 1950s, yet we might still be fitting into the same size clothes as we always have—not because we’ve stayed slim, but because our clothes have grown.

Make customers work for a reward. People put more value on a reward that is not available to everyone. Where there is cognitive dissonance between effort and return, people will be forced to create justifications for working so hard for a small reward, thus increasing their perceived value of the reward.

Manufacturing and then recovering well from a trust issue is a way to create more trust. Machiavelli saw this as a legitimate tactic.

Foot-in-the-door: Gain commitment to a small thing to convince about a big thing.

Door-in-the-face: Ask for a big thing, expecting to be turned down. Then ask for a small thing immediately afterward. Guilt at turning you down makes people more likely to agree to the small thing.

The fear of losing what you already have (your loss aversion) is sometimes as much as twice as powerful as your desire to benefit from a potential gain.


Anger has different effects on judgment and decision making than do other negative emotions. Anger influences how we perceive, reason, and choose.

Use self-generated persuasion: By asking people to “sell” the concept, they get more personally convinced of its merits.

A 2011 BBC documentary on “Superbrands” found that an MRI scan of an Apple fanatic suggested that Apple was actually stimulating the same parts of the brain as religious imagery does in people of faith.

Use anonymity to encourage repressed behaviors. People will do more when they’re anonymous than when they’re identifiable.

Godwin's law, coined by Mike Godwin in 1990, which states, "As an online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches one."

John Suler, professor of psychology at Rider University, names six factors that contribute to what he calls the online disinhibition effect:

  • You don’t know me: Being anonymous provides a sense of protection.
  • You can’t see me: Someone’s online embodiment is different than that person’s true self.
  • See you later: Online conversations are asynchronous. There is nobody to instantly disapprove of what is said.
  • It’s all in my head: It’s easier to assign negative traits to people you don’t interact with face to face.
  • It’s just a game: Some people see the online environment as a kind of game where normal rules don’t apply.
  • We’re equals: The reluctance someone might feel to speak his mind to an authority figure is removed when it’s not clear who is or is not an authority figure.

Happiness rarely triggers commerce. Unhappiness often does. We buy because we are dissatisfied. And this dissatisfaction is often created by the advertising that offers to remedy it. Roy H. Williams

Fear is used overtly in the selling of several types of product. Product categories such as vitamins (fear of ill-health), child safety (think of the children!) and home security (fear of strangers) tend to be high on potential drama so that they can then show that they have solutions that will remove the need for fear.


That makes us inequality averse to use a term from economics. In other words, we hate feeling like we’ve lost out. That feeling of deprivation, inferiority, or shame is the basis of destructive envy.

Create desirability to produce envy. An object must be desirable for envy to work as a motivating force.

  • Secrecy: Being one of the few in the know about an item.
  • Scarcity: Small numbers, low availability of the item.
  • Identity: Identify the item with a desirable lifestyle, person, or activity.
  • Aesthetics: The item is pleasing to look at, hold, and use.
  • Functionality: The item solves a problem nobody else is solving.

Apple hits all these marks with its hardware.

In his book Emotional Design, Don Norman states that we are much more emotionally attached to products for which we feel some involvement (see IKEA Effect). Kickstarter’s whole business model could be described as making people feel ownership before they’ve bought a product, or indeed before it’s even been made.

Let users advertise their status Encourage users to build and advertise their status within a community. In social media circles it might be the number of “likes,” recommendations, mentions, back links, badges, or followers.

“Sent from my iPhone” e-mail signature text for iOS devices got well rewarded for their work. It is the perfect embodiment of effortlessly viral aspirational content. It remains there because it’s boastful in a socially acceptable way.


When we lust after something we stop thinking rationally. We look only for additional reasons to have it, not for reasons to abstain.

Pratfall Effect: The tendency for interpersonal appeal to increase or decrease after an individual makes a mistake

Reciprocity: It doesn’t matter whether you like the person who did you a favour, you still feel obliged to reciprocate and often to do so above the level of the initial favour.

Social commentary on users’ lack of awareness of their status with social media services. “Instagram” (Randall Munroe)

Sell the intangible value. Reality is costly to change, perception less so.

  • Instead the intangible value is assigned by our perceptions of and relationship with the object. It’s the emotional aspect of this intangible part of the value equation that generates lust.
  • Making lemonade from wait-time lemons actually added to the intangible value of spending a day at a Disney theme park. Instead of just going for the rides, people go for the emotional ambience of the entire park. Disney cleverly found a way to make people value the thing that could have been its downfall.

Make a request in order to be seen more favourably. The Ben Franklin effect shows that people who have done us a favour see us in a better light. Ask customers to do a small favor for you. Thank them for it after they are done, but don’t return the favor immediately. Now, having done an unreciprocated favor for you, they must justify it to themselves by believing that they truly like you.


Greed happens when people pursue their own agenda at the expense of others, leading to selfish or spiteful behavior.

Gambler’s Fallacy: We believe that a win becomes more likely after a series of losses.

Reinforcement Schedules

  • Continuous: every stimulus was associated with a reward. The dogs would stop responding (drooling) quickly if no food appeared after the bell was rung. (Pavlov)
  • Partial (Operant Conditioning): sometimes withholding the reward for a correct behavior led to the animals continuing to exhibit the behavior for longer (B. F. Skinner)
  • A partial reinforcement schedule is much harder to break than a continuous reinforcement schedule.
  • Pavlov made use of a built-in reflexive behavior (drooling) to form an association with a preceding condition (a bell ringing). In contrast, Skinner was performing operant conditioning. If the bird did the right thing, it received a reward as a consequence. What does that mean for us? Well, Skinner’s conditioning was active, whereas Pavlov’s was passive.

The Dunning-Kruger Effect: Unskilled individuals suffering from illusive superiority, whereas skilled individuals suffer from illusive inferiority. Make rewards seem due to skill, not luck. Requiring action to get a reward increases the perceived value of the reward.

The best perceived value occurs when the barrier to winning requires just less than the amount of effort or risk that would make a customer decide not to act (play the game).

Facebook, Twitter, and Google track individuals as they venture beyond its walls with “Like,” “+1,” and “Tweet” buttons on other sites, and with the option to use Facebook, Google or Twitter credentials to log in to other sites. They then target behavioural ads based on their actions once they return to the walled garden.

Humans aren’t good at judging absolutes. They’re better at judging comparative values. This perceptual contrast can play tricks on you. (Anchoring). Always have a secondary object that is sufficiently similar to your primary object to be considered a good comparison, but sufficiently less desirable to create perceptual contrast.

The Golden Rule of Persuasive Technology (Berdichevsky and Neuenschwander, 1999)

"The creators of a persuasive technology should never seek to persuade a person or persons of something they themselves would not consent to be persuaded to do.”