Website Optimization Book Review: Influence: Science and Practice by Robert Cialdini

October 08, 2007 (PRLEAP.COM) Technology News
Website Optimization is announcing it’s book review of “Influence: Science and Practice” by Robert Cialdini. Now in its fourth edition, this 262 page book shows readers six main ways people are influenced to say yes. Through the study of human psychology and dramatic examples, Robert Cialdini shows how humans sometimes use mental shortcuts to make decisions. "Influence practitioners" skilled at the art of persuasion can use these techniques to engage these shortcuts to influence our decisions. The book not only illustrates the six persuaders, but shows us ways to defend against these practices when the influencer may not have our best interests at heart.

For the full book review visit:

The Psychology of Persuasion

An experimental social psychologist, Cialdini studied the psychology of compliance. At first he used experiments with students on campus. But Cialdini realized that to truly understand how persuasion works he needed to study how "compliance professionals" work in the wild. For nearly three years he immersed himself in the world of compliance, taking jobs with sales people, fund raisers, advertisers, waiters and the like to see persuasion in action. His goal was to find the main tactics used by these persuaders. Although there are thousands of different tactics that compliance practictioners used to get us to yes, Cialdini found six core influence principles. They are as follows:

* Reciprocation
* Commitment and Consistency
* Social Proof
* Liking
* Authority
* Scarcity

What follows is a summary of the book with examples of the use of each persuasion technique. We also show how each technique can be used on the Web to persuade visitors to say yes.


Humans feel obligated to repay a gift from others. A basic norm of human culture, reciprocation requires that people try to repay, in kind, what another person has provided. This social lubricant ensures continuing relationships, which sociologists say is beneficial to society. In fact all human societies subscribe to this rule of future obligation. Reciprocation is a powerful force. It can overpower other rules such as liking.

Commitment and Consistency

People want to be and look consistent with their words, beliefs, and attitudes. Once we commit to something we want to appear consistent after making the decision. These societal pressures cause us to behave in ways that justify our earlier decision. The key to getting people to comply is commitment. Getting that initial commitment (taking a stand on an issue for example) makes us more likely to agree to requests that are in line with that prior commitment. Personal consistency is highly valued in society. Inconsistent people are viewed as confused and erratic. Being automatically consistent saves us from thinking and spending time dealing with the complexities of everyday life. But there is risk in blind consistency.

Social Proof

One method humans use to determine what is correct is by figuring out what other people think is corrrect. So we look at what other people are doing or believing and follow along. Social proof can simulate compliance with a request by telling the person that many other people have been complying. The author himself uses the principle of social proof on the cover of his book, "Over One Million Copies Sold!" After all, one million people can't be wrong. Social proof is another kind of mental shortcut to save effort. We "make fewer mistakes by acting in accord with social evidence than by acting contrary to it."


Most people prefer to say yes to people that they know and like. We are more likely to comply when a product or service is associated with physically attractive people, positive circumstances or attributes, and people that are similar to us. Recommendations from a friend or someone we know has much more weight than a cold call from a stranger.


There are strong societal pressures to comply with the requests from an authority. Systematic societal pressures have instilled in us that deference to authority is correct conduct. Obeying genuine authories, who possess wisdom, knowledge, and power is a decision-making mental shortcut.


People want to possess what they cannot have. People assign higher value to an opportunity when it is less available. If it is becoming rare it is therefore more valuable. The mental shortcut is if things are more difficult to possess, they are typically better than things that are easier to possess. So we use an item's availability as a quick proxy for its quality. One other aspect of the scarcity principle is that we hate to lose the freedoms we already have. This desire to maintain our options is called psychological reactance. "According to the theory, whenever free choice is limited or threatened, the need to retain our freedoms makes us desire them (as well as the goods and services associated with them) significantly more than previously." (Cialdini 2007). So we react against any restrictions on the prior access of an item, desiring it more than before.


Influence shows us how six core techniques are used to persuade people to comply with requests. Cialdini shows how we take mental shortcuts to quickly arrive at decisions to save time and effort. By tapping into these "click, whirr" behaviors, people can use these techniques to persuade people to say yes. There are two books out titled "Influence" by Cialdini, "Influence: The Psychology of Persuasion" and "Influence: Science and Practice." Even though the first is newer than the second, I recommend the second book as it has more meat in it, including summaries, questions for students, letters from readers, and more. The first book is more of a layman's version of the second. Both books have the much of the same information and stories. Highly recommended.
Further Reading

Influence at Work
Cialdini's web site for more information on the psychology of persuasion.

Cialdini, R. B., "Influence: The Psychology of Persuasion," revised edition
(New York: Collins Business Essentials, 2007), 245. They layman's version of his persuasion book. Cialdini, R. B., "Influence: Science and Practice," 4th ed.,
(Needham Heights, MA: Allyn and Bacon, 2001). A more scholarly version of the book with cites, chapter summaries, and questions and answers for students.

About the Author

Andy King is the founder of five website developer-related sites, and the author of Speed Up Your Site: Web Site Optimization ( from New Riders Publishing. He publishes the monthly Bandwidth Report (, the semi-weekly Optimization Week (, and Speed Tweak of the Week (