An Event Apart: Persuasive Design

by Luke Wroblewski October 23, 2011

At An Event Apart in Washington, DC 2011 Andy Budd outlined how the principles of persuasive design in the real world can be applied to creating Web sites. Here's my notes from his talk:

  • Slot machines are the ultimate example of persuasive design: noise cancelation, timed play, small payouts over time (loss aversion), etc. There’s a lot of design decisions behind the experience.
  • Design is all about making choices: color, placement, hierarchy, and more tell a story that is absorbed (mostly unconsciously).
  • Designs are trying to influence us everywhere we go in the world. Product designers and movie directors both play to our emotions to entertain us or influence our purchases. Even architecture (places we live/work in) influences how we use physical spaces.
  • Some designs are created to dissuade or restrict negative behavior. Example: park benches are uncomfortable or curved to prevent people from sleeping on them.
  • We’re exposed to thousands of branding messages per day. We see more ads in a year than our grandparents saw in a lifetime.
  • Brands use their understanding of a human behavior to increase consumption. The Alka Sletzer campaign pushed the idea that you use two tablets (plop, plop, fizz, fizz) and doubled sales overnight.
  • Subconscious influencers of behavior: Supermarkets use space design to move you past potential purchases on the way to the most common ones. Increasing the volume of music in the bar increases the amount of alcohol consumed. Retailers use scents, background music, and more to divert interest, relax people, and get them to buy more.
  • We all think it is not affecting us, but the data shows otherwise.
  • Some persuasive design techniques are designed to encourage positive behavior not just consumption. Examples: use the stairs, recycle, etc.
  • Marketing creates shortcuts to help people overcome the paradox of choice. When those messages are truthful, it’s a benefit. When they are false, they can be misleading.

Persuasive Design Techniques

  • Choice architecture: the decisions we make push people in one direction or another. To do this we need to understand how the brain works. What are the cognitive biases we have built in: loss aversion, selection bias, operant conditioning, framing, focusing effect, etc.
  • Authority & trust: people will follow instructions when they come from perceived authority figures. Design has a powerful effect on creating trust. We believe what is beautiful is good.
  • Halo effect: first judgments cloud us for rest of our interactions. People stick with initial decisions.
  • Trust indicators: show pictures of customers, include a phone number, use professional design, ratings, etc.
  • Where we put things (physically or in digital layouts) has an influence on design. Placing expensive wines on the top shelf in a store frames how much wines should cost and prompts you to buy mid-range wines vs. cheapest ones on the bottom. A small target on urinals can reduce spillage by up to 80%.
  • Use sensible defaults in pricing pages. Present a higher and lower end option as well.
  • Persuasion takes the cognitive bias away and makes things a bit easier to use. It’s kind of like usability.
  • Social proof: strongly influenced by the behavior of others. Examples: long lines in front of bars, meal deals at restaurants early in the day.
  • Online, you can show how popular you are by including testimonials, usage numbers, and more. When you are around people you know or trust, the more you feel at ease.
  • To influence people, show them the kind of behavior you expect.
  • Loss aversion: limiting supply to increase the speed of sales. TV shopping channels pay off loss aversion –we hate to miss out on opportunity (even though we might not need what we are buying).
  • Limiting supply encourages people to share more consciously. Deal of the day sites are built on this principle.
  • Liking and likability: associating products & services with known celebrities makes a connection between new things and known entities/personalities.
  • Make it easy for people to like you: small details can create personality and make yourself more memorable.
  • Gifting and reciprocity: giving things to people creates a sense of debt, which can be redeemed later. Free shipping and starting funds (free initial money) is a classic example of this online.