FAYETTEVILLE, Ark. — Purchasing a new car may provide a great new ride, but it also comes with an additional payment each month. The daycare across town might be cheaper than the one next door, but it’s an extra five-mile drive each day. Decisions like these can be complex and include some features that create resistance. A University of Arkansas professor has come up with a method to measure resistance as it occurs.

Psychology professor Eric Knowles was invited to present his study, “Resistance and Persuasion: Measuring Resistance,” at the Midwestern Psychological Association conference in Chicago early this month.

Knowles’ “resistometer” allows him to monitor participants’ resistance levels in reaction to what is occurring during experiments. The resistometer is a computer outfitted with a large steering wheel. Participants view a message, advertisement or request on the computer screen, and turn the wheel to move a pointer along a continuous scale from reject (3) to accept (-3) or dislike (3) to like (-3). The participants receive training and practice before the experiment begins.

While promotion-based strategies are commonly used and have been extensively tested in advertising and marketing, resistance has not been widely studied. In the past, resistance assessments were conducted by presenting volunteers with a message or request, then asking them afterwards to list the relevant thoughts they had during the presentation. The participants would then rate their thoughts as supporting or disputing the position in the message.

This list method does not indicate when resistance formed during the message.  It may miss thoughts participants had during the message, or the participants may include new thoughts constructed while they are listing.

Online measures of resistance like the resistometer, on the other hand, provide a contemporaneous measure of resistance. The continuous and variable measurement of resistance allows assessment of what parts of the message invoke resistance.

Measuring resistance and the processes of influence can help people in sales, nonprofit organizations, management or in their own families.

“One of the most useful applications for my research has been in my own life, identifying my own resistance and dealing with it,” Knowles said.

In two resistance experiments, participants viewed video messages, moving the steering wheel as their reactions changed from liking what they heard to disliking what they heard. One videotape explained an increase in students parking illegally on campus, and stated that parking fines would be doubled as a possible solution to the problem.

As the participants learned about the increase in illegal parking, their resistance ratings gradually increased, to almost 0.5 on the scale. Within about two seconds after hearing that fines would be doubled, the resistance ratings jumped from less than 0.5 on the scale to nearly 1.5 on the scale. Just then the students learned that each student would receive two “park anywhere” passes each week, and the numbers dropped to negative levels, showing that participants liked or accepted the message at that point.

Knowles was able to predict, and then pinpoint on a graph, when the participants’ levels of resistance rose and what prompted the changes. The results of the resistance tests were as he’d expected.

When Knowles used the resistometer in an “argument strength study” to determine whether strong arguments generate less resistance than weak arguments, he was surprised at his results. Thirty-nine participants were assigned to hear the same message advocating that all computer use on campus be monitored and filtered. Nineteen participants were randomly assigned to hear strong arguments for the change, while 20 participants were assigned to hear weak arguments. The speaker, introduction and conclusion in both messages were the same.

“We gave them six dumb reasons for monitoring and filtering computer use, and it didn’t make as much of a difference as we thought,” Knowles said. “There was more resistance to hearing the topic than to hearing the six terrible reasons why.”

Both groups showed a spike in resistance upon hearing what the message advocated. The group hearing the weak arguments remained resistant, never dropping below 0.5, while the group hearing strong arguments rapidly dropped its resistance to acceptance, nearly -2 on the scale. While Knowles expected them to be resistant to the message, he thought the weak arguments would only increase the participants’ resistance.

For nearly a decade, Knowles has been studying strategies for reducing resistance. He identifies two strategies for persuasion and change: promotion-based strategies and resistance-based strategies. Most advertisements or attitude changes use promotion-based strategies, which increase desire by playing up incentives. These strategies attempt to overwhelm resistance by making a product or request appear attractive and demonstrating its benefits.

Resistance-based strategies, on the other hand, attempt to reduce or remove resistance by identifying its sources and attempting to remove them directly or psychologically. Knowles calls these strategies Omega Strategies, after the Greek symbol for resistance.

“You can overwhelm the resistance, but that doesn’t change it,” Knowles said. “Resistance-based persuasion that reduces resistance allows a person to make a decision with less ambivalence.”

A distraction strategy inserts unusual phrases into a message, which in experiments made the message more persuasive. The strange phrasing disrupted the listener’s attention and made them more aware of the final persuasion point.

Knowles’ research also has shown that messages are more persuasive when resistance is acknowledged, as in “I know you may not want to do this, but.” He has also identified the consuming resistance strategy, in which the persuader attempts to get the resistor to “use up” resistance before hearing the actual persuasive message. This strategy is based on Knowles’ theory that resistance is a finite resource, much like behavioral control, that becomes less efficient as it is used.

Much of Knowles’s work has been funded by National Science Foundation grants. With the help of various psychology students, Knowles has been devising experiments to test the efficacy of each tactic. He partnered with Jay A. Linn of Widener University to co-edit a book, “Resistance and Persuasion,” which was published in 2004 by Lawrence Erlbaum Associates.