The Science of Online Persuasion – Part 2

Marketers have been trying to persuade people for centuries. From the street corner huckster to the modern day sales person, we are inundated, both consciously and non-consciously, with people working to influence our perception and convince us to take some type of action.

In Part 1 of this article, we discussed the principles of Reciprocity, Commitment/Consistency and Social Proof. For this article, we’ll look at three additional psychological principles - Authority, Liking and Scarcity.

Taken together, these principles have been extensively studied by Dr. Robert Cialdini and presented in his very popular book Influence: The Psychology of Persuasion. While the book was originally written in 1984, these principles are immediately applicable to today’s digital marketing strategies and we use them here at for the A/B testing programs we run for clients.

Let’s look at these final 3 principles in more detail.

Principle #4: Authority
When we meet someone who has solid credentials and a history of being a thought-leader in his/her chosen field, we tend to pay more attention to what they say and usually will defer to their ideas and recommendations.

Authority also works at a non-conscious level and when we feel a bit uncertain about something, a person of authority can usually tip our thoughts and perceptions quite easily. It’s normal human behavior that during times of uncertainty, we look outside of ourselves to find validation and guide our decisions.

How does this principle translate to your website? Testimonials from legitimate recognized authorities can help persuade your site visitors to take action. The principle of Authority may seem synonymous with social proof, but social proof includes the thoughts/opinions of many, whereas the use of authority concentrates on the perceived expertise, status or power of a single person or business entity.

Here are some suggestions on how you can create a sense of authority within your own website.

  • Use of academic titles

  • Listing of certifications

  • Past work and case studies with well-known companies or famous people
  • Site design & photography (people will quickly evaluate a site by visual design alone)
Principle #5: Liking
This principle is based on the psychology that we are more likely to comply with someone if we like them. The key element of ‘liking’ is that we have some commonality and shared interests. Establishing likeability online can be a bit challenging because there is no face-to-face interaction, but your ‘About Us’ page is a good place to start. Not only should your ‘About Us’ page establish authority and expertise, but it should also show the human side of your business.

Here are some other ideas and suggestions for establishing likability within your website:


  • Physical attractiveness – When it comes to websites, solid design, professional photography and attractive people can do a lot to draw visitors in.

  • Similarity – We naturally like people that are similar to us in terms of interests, opinions, personality and background. Understand your visitor personas and craft copy, headlines and value propositions that show you understand them.

  • Contact and Cooperation – We feel a sense of common purpose when working with others towards a common goal. For online businesses, this can be expressed by supporting charitable organizations or working to make your business more environmentally friendly.

  • Conditioning & Association – We like looking at people we find attractive, and thus become more favorable towards the products and services behind them.

Principle #6: Scarcity
Scarcity is a powerful principle that is tied in to our reptilian brain stem, which evolved to serve the needs of survival. When resources are scarce, people can act quite impulsively, leading to irrational behavioral responses. As marketers and business owners, we can use this natural base brain response to our advantage by creating a sense scarcity.

Here are some examples of how you might do this on your own website:


  • Limited number – Item is in short supply and won’t be available once it runs out

  • Limited time tactics – daily deals

  • Holiday specials

  • Clearance Sales

  • One-of-a-kind specials

  • Anniversary specials

  • One-off special events

  • Pre-orders
One thing to mention is the importance of testing these principles on your website as opposed to just blindly following them and hoping for the best. By A/B testing all these ideas, you’ll be able to better quantify their overall business value. In addition, testing different variations of each principle will allow you to methodically find the right types of headlines, images, copy and offers that ultimately produce the best results.

If you’d like to learn more, check out this introductory video titled ‘What Is A/B Testing?

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