The Study of Computers
As Persuasive Technology

By John W. Shaffer

Captology is a made-up word meaning: the study of Computers As Persuasive Technology (CAPT-ology). B.J. Fogg is a professor at Stanford University and runs the Persuasive Technology Lab there. He was instrumental in developing the field of Captology. He said, "Simply put, a persuasive computer is an interactive technology that changes a person's attitudes or behaviors." (Fogg, no date, 1) A critical aspect of Captology is persuasion. He defines persuasion as, "an attempt to shape, reinforce, or change behaviors, feelings, or thoughts about an issue, object, or action." (Fogg, no date, 1) Captology includes two varieties of persuasion: "macrosuasion" and "microsuasion". Macrosuasion refers to products that are used exclusively for persuasion. Microsuasion refers to products that include components meant to persuade. (Cheng, 2003)

According to Dr. Fogg, "One key point implicit in my definition is that true persuasion must be the result of an attempt to change attitudes or behaviors; in other words, persuasion requires intentionality." (Fogg, no date) From this we can deduce that all use of computers is not Captology. There are a number of methods to use a computer to instruct or inform that do not also include an attempt to persuade the intended audience. There are also times when persuasion occurs but without any intent on the part of the developer. "A computer qualifies as a persuasive technology only when those who create, distribute, or adopt the technology do so with an intent to affect human attitudes or behaviors." (Fogg, no date) In other words computers require human interaction with the intent to persuade to be considered persuasive technology. "Most software development is about functionality and usability, and only incidentally about modifying the user." (Grosso, 2003) Since the intent to persuade is a key component of captology, software programs, web sites, or other computer technology developed without such intent do not qualify as captology.

The ability to use computers as persuasive technology has increased sequentially with the huge surge in internet usage over the last decade. However, the internet is not the only way to use computers as persuasive technology. Computer technology can be used in many other ways to persuade people.

Dr. Fogg developed what he calls a functional triad for captology. It describes three different ways people use or respond to computer technology. "First, the computer as tool makes some behavior easier to do; an example is a pocket calculator. Second, the computer as medium provides an experience to the user; an example is a virtual environment. Third, the computer as social actor creates a relationships between the user and the computer; a digital pet is an example of this." (Cheng, 2003) We will look more closely at the three parts of this functional triad in several examples below.

One example of captology as a tool is companies using automated instant messaging to send users alerts. This is also referred to as nagware. Another example of captology as a tool is using computer technology inside products intended to persuade people a certain way. Baby Think It Over®, discussed more fully in the next paragraph, is an example of this. An example of captology as medium is a simulation program designed to encourage individuals to take a particular action. Examples of captology as a social actor are the various wizards embedded into programs that attempt to encourage users to perform tasks a certain way.

Computer as tool: Realityworks, Inc. has many programs designed to influence behavior. One is the Baby Think It Over® Program (BTIO) designed to educate young people about parenting responsibilities. A main feature of this program is a life-like doll that simulates many infant needs. Participants are required to care for the dolls just as they would an actual baby. According to the mother of a 13 year old BTIO participant, "Before she had BTIO, she wanted a baby and couldn't wait to get old enough to have her own….Well, she had BTIO for 5 days and by the 4th day she was writing in her diary how much she did not like the baby and that she was not going to have a baby until she was in her 30's if ever." That quote speaks strongly to the persuasive power of BTIO (Realityworks, 2004).

Figure 1. Baby Think It Over® Program (BTIO)

Computer as medium: The Century Council, a non-profit organization that fights against drunk driving, has several CD-ROM based programs that attempt to discourage people from drinking and driving. These include Alcohol 101, targeting high school students, Alcohol 101 Plus, targeting college students, and the Blood Alcohol Educator, an interactive program that teaches adults how drinking affects their blood alcohol concentration. Alcohol 101 Plus is an award-winning interactive program set on a virtual campus. It targets students thought to be particularly at-risk such as Freshmen students and those in the Greek system. The program is used at hundreds of universities and colleges across the nation.

Figure 2. The Century Council's Alcohol 101 Plus

Computer as social actor: Dole 5 A Day provides a very engaging web site including a chat room and an interactive program targeting young children. The purpose of the interactive program is to encourage children to get their five to nine recommended servings of fruit and vegetables each day. It provides several areas from designing a 5-a-day recipe, to tracking your fitness, to games and crossword puzzles. It even has over ten songs presenting information about eating the proper amount of fruit and vegetables. I found this site particularly engaging. When I was reviewing this site my 9-year-old son walked up and commented, "That's a cool web site." Considering his lack of interest in both fruit and vegetables, that is a pretty good recommendation.

Figure 3. Dole's 5 A Day

In order for any computing technology to influence a person's behavior it must be seen as credible. Therefore, one of the largest areas of research concerning captology has been in the area of credibility. Credibility, which can also be thought of as believability, is important in several different situations. Any time a computer contains data or information for users, that data or information must be seen as credible. Any time a computer is used to teach or instruct users it must be viewed as credible. Also, whenever computers run simulations they must be considered credible. However, user variables affect credibility. The credibility of computer technologies varies with user's experience. A novice user might view computers as more credible than an expert user. A user who needs information more might be more inclined to believe the information than a user who does not need the information. (Tseng and Fogg, 1999)

Much research about captology has been conducted in association with the Stanford Web Credibility Research organization, part of the Stanford Persuasive Technology Lab. A web site's credibility depends largely on how it is designed. Developers should, "Make it easy to verify the accuracy of the information on your site." Developers should also "Design your site so it looks professional…" These are just two of the ten guidelines for increasing credibility of a web site listed in a table on the Web Credibility Research web site. The table also references research supporting each of the ten guidelines; it has links to much of the research. (Fogg, 2002)

Captology is still a relatively new field; consequently, much research still needs to be accomplished. Dr. Fogg mentions seven directions for research and design. Among them are, "Captology should focus on interactive technologies that change behaviors." And "Captology should focus on 'what is' and 'what could be'." (Fogg, no date, 2) These, and the other areas of research Dr. Fogg mentions, will surely provide valuable research directions in the field of captology for years to come.


Cheng, Karen. (May 5, 2003). Monthly Program: March 11, 2003, Meeting Report. Using Computers to Change What People Think and Do: Insights into Captology. B.J. Fogg. Retrieved Feb. 16, 2004, from San Francisco Bay Area Chapter of ACM SIGCHI Web site:

Fogg, B.J. (May 2002). Stanford Guidelines for Web Credibility. Retrieved Feb. 16, 2004, from Stanford University, Stanford Web Credibility Project Web site:

Fogg, B.J. (n.d., 2). Captology: Seven Directions for Research and Design. Retrieved Feb. 17, 2004, from Stanford University, Stanford Persuasive Technology Lab Web site:

Fogg, B.J. (n.d., 2). Persuasive Computing: A definition and the role of intent. Retrieved Feb. 17, 2004, from Stanford University, Stanford Persuasive Technology Lab Web site:

Grosso, William. (Jun. 21, 2003 08:52 AM). Captology: A Bad Name for an Interesting Idea. Retrieved Feb. 16, 2004, from O'Reilly Developer Weblogs Web site:

Realityworks. (2004). Parenting Education Testimonials. Linda Avila. Retrieved Feb. 18, 2004, from BabyThink It Over® Program, Parenting Education, Realityworks, Inc. Web site:

Shaffer, John. (2004). Email:

Tseng, Shawn and Fogg, B.J. (May 1999). Cedibilitiy and Computing Technology. Communications of The ACM, 42, 39-44. Retrieved Feb. 16, 2004 from Stanford University, Web Credibility Project Web site:

Author Note


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