Designing for persuasion

Erdem BilicanFormer UX WriterSHERPA

“Emotions shape all activity in adaptive ways. In the absence of emotional markers, decision making is virtually impossible.”  

Saver & Damasio (1991) 

When it comes to the human mind, there are a plethora of things that are really interesting. But especially our decision-making process, and how external factors can influence it, is truly an astonishing subject. For one, we tend to think that we are rational, logical beings, always with sound reasoning; however, there are some solid studies that posit “emotions constitute potent, pervasive, predictable drivers of decision making.” On top of that, we also know that emotions are not untouchable and can easily be influenced by many external factors. So if that’s the case, how can we utilise design to persuade users to take specific actions? 

Let’s look at the concept of persuasive design and discover how some of the psychological gimmicks that influence how we behave can be applied to the field of design.

Social proof

One of the strongest influences on human behaviour is the principle of social proof. Robert Cialdini states in his renowned book, Psychology of Persuasion:

“We view a behaviour as more correct in a given situation to the degree that we see others performing it. Whether the question is what to do with an empty popcorn box in a movie theatre, how fast to drive on a certain stretch of highway, or how to eat the chicken at a dinner party, the actions of those around us will be important in defining the answer.” 

So, to factor in this principle, we could take advantage of social proof in our designs. If we’re designing a user flow for a non-profit company that depends on taking donations from the company’s website, for example, adding a persuasive pattern by displaying the number of contributors, e.g. “128 people have donated today!”, may prove effective in directing users to desired outcomes. You can also see similar examples on a lot of e-commerce websites as well. 

The critical part of this approach is we also need to consider the level of persuasion as it could become manipulative in certain situations. While incorporating elements to display social proof, the emphasis should be on the objective facts rather than creating a FOMO effect or simply misleading users with non-factual information.

Scarcity

There is an interesting experiment conducted in 1975 by Worchel, Lee, and Adewole, where the researchers asked people to rate chocolate chip cookies, to understand how the concept of scarcity affects the decision-making process. Briefly, what they did was:

“They put 10 cookies in one jar and two of the same cookies in another jar. The cookies from the two-cookie jar received higher ratings—even though the cookies were exactly the same.” 

Also, there is a famous anecdote, the so-called Water-diamond paradox, that sums up the subject pretty much: 

“…we purchase water, which is necessary for our survival, very cheaply, whereas we pay much more money for a diamond, even though it is not required for our lives at all (Smith 1776/1937). This paradox critically points out that object value is not merely determined by usefulness but also by availability.” 

So, it safe to say that this principle, creating the illusion of scarcity, automatically triggers a kind feeling of urgency and an increase of value in our minds so we perceive objects that are scarce as more desirable and valuable. User experience designers can make use of this psychological effect to create similar results. For one, you can see etsy.com using badges like “Only 1 available and it’s in 1 person’s cart”, or amazon.com displaying a counter that says “Ends in 10h 28m 15s”or “only 2 left in stock”, and so on… 

There are many more examples out there, but as Nielsen Norman Group suggests, some common patterns you can use in your design include limited time and quantity, limited inclusion, and limited information.

Authority

Think about the podcasts you listen to, Ted talks you watch, the doctor you visit or maybe the professor at your university. A random person’s opinions may not be so valuable for you, but you most likely will listen to and agree with the views of individuals who are experts in their fields. The “authority principle” points out our tendency to respect or obey authority figures and highly value their taste & opinions.

As Nielsen Norman Group points out: “UX professionals can take advantage of the authority principle to increase the credibility of their designs. A few elements that can increase trust: “

  • Photos of people in authority positions (or people dressed like they’re in authority positions) — doctors or scientists dressed in white lab coats, or lawyers dressed in suits 
  • Symbols of authority — for example, the caduceus or staff of Hermes, a popular symbol for the practice of medicine, or the scales of justice for law-oriented sites 
  • Logos of reputable organisations 
  • Quotes and endorsement from experts, celebrities, and other authority figures

You can also add list certifications, awards, prominent customer testimonials, etc., to the list to take advantage of this principle if you want to get your users attention more quickly. 

The human mind is a mystery, and we’re still exploring how it works. There are other elements and concepts exerting influence on the decision-making process like reciprocation, commitment & consistency, liking, and there will be many more as we understand how the human mind works better. Yet, tested and validated, the concepts of social proof, scarcity and authority may be helpful for you to create more persuasive products. And remember that persuasion in design is just a little nudge to users’ direction, not manipulation or trickery.