The thesis of this dissertation is that the humor is effective for persuasion. In order to measure it successfully, one must first offer and then empirically test a theoretical explanation for it. After reviewing both humor theory and persuasion theory, predictions were made about when humor would be effective in support of persuasion.

The Ethics Challenge was selected as an example of the use of humor in persuasion. In a carefully controlled experiment, elements of humor were removed from that game. Whenever removing a humor element from the game inhibited its effectiveness, it was inferred that the element had been playing an important role in the persuasive effect of the Ethics Challenge.


Removing All the Humor

Removing the humor altogether inhibited the Ethics Challenge's ability to persuade participants to consult the ethics office. This finding alone supports the contention that humor can add to the effectiveness of a persuasive message. In fact, some experiments have stopped at this point, after comparing a humorous treatment to a non-humorous treatment .

However, the current study went further. It treated cartoon drawings and ironic wisecracks separately to assess their individual effects, and then compared these with the combined effects of cartoons and wisecracks together. These results will be discussed below.

Removing all of the humor also reduced the likelihood that participants would increase their agreement that the company was serious. The interpretation of the word serious was left up to the participants, and some of them took it to mean that the company was serious about ethics. It seems significant, however, that the company was taken more seriously (however interpreted) when using humor than when not using it. This should allay fears that the use of humor in the Ethics Challenge trivializes ethics or makes the company's position on the matter seem frivolous.

Removing Cartoon Drawings

It was expected that cartoon drawings would elevate the mood of participants and make them more amenable to persuasion. However, removing the cartoon drawings seemed to have very little effect. The cartoons did not even seem to have elevated participants' mood. As surrogates for mood, consider their approval ratings of elements of the experiment. There was no significant effect on their appreciation for mini-cases or the facilitator, and those with cartoon drawings actually rated the multiple-choice answers as significantly less entertaining than those without cartoon drawings. Thus it seems unlikely that their mood was significantly elevated.

Removing the cartoon drawings did not significantly reduce persuasion either. Although intention to consult the ethics office fell slightly when the cartoons were removed, that effect (p = .061) did not reach statistical significance. Furthermore, there was no correlation between finding Dilbert funny and reporting increased intention to consult the ethics office. It seems that the cartoon drawings on their own created an insignificant effect.

These findings were contrary to the enthusiastic claims of many writers in the field of education and advertising but consistent with the results of earlier scholars , who established that the persuasive effect of cartoon illustrations is actually quite small.

Removing Ironic Wisecracks

It had been expected that the ironic wisecracks would serve as a distraction task, because of the need for participants to decode both their literal and ironic meanings. It had further been expected that this distraction would enhance the effects of the persuasive message.

The results of the current study confirmed that the use of ironic wisecracks supported the effectiveness of the persuasive message. Removing them greatly reduced the effectiveness of the message. It also greatly reduced participants' agreement that the company was serious. The results of this particular manipulation were the strongest in the experiment, although the next manipulation to be discussed (inhibiting the self-effacing context) was a very close second. It remains for future research to determine whether humorous irony performs this task any better than non-humorous irony (such as bitter sarcasm, for example).

Inhibiting the Self-Effacing Context

In general, there is strong evidence that source credibility is enhanced when a source speaks against his/her own interests. Using self-effacing humor is one example of speaking against (or seeming to speak against) one's own interests.

It had been assumed that ironic wisecracks, in the context of Dilbert's well-known anti-management perspective, would constitute self-effacing humor. What could be more self-effacing than managers using humor that pokes fun at management?

Furthermore, removing either of the humor elements was expected to inhibit that self-effacing context. The ironic wisecracks alone could be taken as simple sarcasm, with no reason to consider management as the butt of the joke. The cartoon drawings alone would introduce the Dilbert context, but without any humor. Only the two elements used in combination were expected to constitute self-effacing humor.

To test the specific effectiveness of the self-effacing humor combination, the intact version was compared against those with either element of the humor removed, but not both. It was expected that disrupting the self-effacing humor combination (by removing either element of the humor) would decrease participants' assessment of source credibility, and thus reduce persuasion.

The link with credibility was supported. Interfering with this combination significantly reduced participants' agreement that the company was serious. Thus it seemed that the combination had been producing the predicted effect on credibility. However, the expected power of credibility to overpower other effects and deliver greatly increased persuasion was not demonstrated. The self-effacement seemed to improve credibility, and did boost persuasiveness significantly, but the effect was not quite as strong as expected. It did not overshadow the effect of the irony.

There is a possible explanation for this in the literature. Brian Sternthal, the writer of an authoritative review on the topic of humor in advertising , found an interesting effect in another study. Speakers with otherwise low credibility were more effective than high-credibility sources when addressing certain audiences.

In particular, the low-credibility sources were successful with low-involvement audiences of the converted (people who already supported the position advocated by the speaker). Apparently the sympathetic audiences helped such speakers along with internal elaboration on their arguments . In other words, for issues with which audiences were not deeply involved, and with which they already agreed, a low-credibility speaker was actually more convincing.

Participants in the current study were young students with very little work experience. As a result, they were probably less involved in the situations described in the ethics mini-cases than a full-time employee might be. They might never have experienced such situations themselves. Furthermore, they were probably a sympathetic audience for the suggestion that bad behavior should be reported. Some writers argue that today's youngsters (Generation X) are more likely to report an offense than their older counter-parts (Baby Boomers), because their sense of loyalty to society seems to outweigh their sense of loyalty to individual peers. The participants in this experiment were not deeply involved, and were a sympathetic audience. Perhaps they were not quite as sensitive to credibility as usually expected.

However, it is important to keep in perspective that the removal of the self-effacing context of humor did affect source credibility and persuasion strongly. Its effect was nearly equal to that of removing ironic wisecracks and, in an early study, had actually been found to be higher . The effect of this element of the humor is indeed very strong.

So, removing cartoon drawings had little effect. However, removing ironic wisecracks or interfering with the self-effacing context of the humor had two powerful effects. It significantly reduced the game's effectiveness at persuading participants to consult the ethics office, and significantly reduced their rating of the company as serious.



Complex interaction effects are generally expected in humor research. Most people seem to assume that humor is very subjective (in the eye of the beholder), and think that its effects will vary widely according to demographic factors and personal tastes . However, in the current study, this did not seem to be the case.

Few interactions were found. For example, a participant's tendency to provide socially desirable responses did not interact with the effectiveness of the humor treatment at all. Nor did gender, work experience, or time spent living outside of North America. It seemed that the effectiveness of the humor for persuasion did not vary significantly with these variables.

A very specific interaction indicated that those who liked Dilbert better were less likely to be influenced to rely on the legal department. However, they did not show any similar reticence to rely on managers, the ethics office, or the ethics help line. Perhaps those who shared Dilbert's perspective and sense of humor also shared a particular distrust for lawyers.

Dilbert fans were also less likely to increase their agreement that the sponsor was fun after the experience. Perhaps, as seasoned Dilbert appreciators, they were less impressed with the humor offerings in this study than those for whom the Dilbert perspective was more novel.

Those with a stronger sense of humor (in general) were less likely to abandon friends and family as a source of advice after participating in the activity. Perhaps they had a close relationship with friends and family as a result of their high appreciation for humor. On the other hand, perhaps their unusually bright friends and family (who helped them develop such a fine appreciation for humor), constituted reliable sources for ethics advice.

A very weak interaction existed between those who had spent more time living outside of North America and improved capacity to recall the correct answers when humor was used. In other words, for those who had spent the least time in North American culture, the use of humor did not improve their ability to recall the correct case answers much.

This sort of effect had been expected, but it was expected to be much stronger and more pervasive. It was thought that people who had spent less time in North America would lack the shared context to appreciate Dilbert humor. Thus, they were expected to enjoy it less and be less affected by it. Further, it was thought that those from outside of North America would be less accustomed to the idea of bringing humor to bear in an otherwise very serious discussion.

However, although there was some indication that they were less likely to have seen Dilbert cartoons, there was no indication that these participants enjoyed them any less. There was no negative correlation between time spent outside of North America and preference for any of the elements of the humor. Unfortunately, there was not enough data to probe that relationship any further.

Correlations among questions about Dilbert were quite high. Two-thirds of the people who had seen Dilbert found him funny, while half of them agreed with his ideas. With correlation information, it is impossible to judge directions of causation. Perhaps agreeing with Dilbert made him seem funny, or vice versa, or perhaps the two phenomena are both the effects of some common cause.

The three tests of the sense of humor were also highly correlated, especially the initiation and appreciation instruments. Apparently those who appreciate humor initiate it (and vice versa), but do not necessarily use it as a coping mechanism. Some, who were neither initiators nor appreciators, nonetheless used humor as a coping mechanism at work.

The youngest students (who had most recently been in high school) recalled correct answers better, as did those who had spent more time in North America. Presumably these participants had fresh study habits and some familiarity with the North American style of learning.

Older participants were more likely to be influenced by the humor to increase their agreement that the company was ethical, caring and especially fun. This may mean that the older participants were more open-minded on the topic but, given the severely restricted age range in the current study, it would not be prudent to read much into that particular result.

Efficacy of Instruments

Scholars often question the accuracy of measures of the sense of humor. Since people do not want to declare lacking a sense of humor, or having a bad one, it is often opined that humor tests are confounded with socially desirable responses. In the current study, the Marlowe-Crowne Social Desirability Scale was administered to test that assertion. In general, this common sense notion seemed to be wrong.

Except for a very small correlation between socially desirable responses and the Coping Humor Scale (a Pearson correlation of .131; p = .088), the humor tests were completely vindicated. There was no significant correlation between social desirability and any of the humor scales. Furthermore, correlation analysis supported the successful design of the humor tests. The three tests were sufficiently correlated to reassure investigators that they were measuring the same phenomenon, but not so correlated as to indicate that they were redundant.

The mini-cases that had been selected as pre-tests of skill were also vindicated when compared with the social desirability scale. Those who tended to give socially desirable responses actually scored lower on the ethics mini-cases than others did. The cases were able to distinguish those tended to give socially desirable responses.

The Ethics Challenge itself fared particularly well. Even with many important elements of the activity removed for this experiment (including all the group interaction, game pieces, board activities, wall graphics, and the introductory videotape), the game delivered most of its intended effects. Participants reported more intention to rely on managers, the ethics office, the ethics help line, and the legal department. They reported less intention to consult co-workers or friends and family. They increased their agreement that the sponsor (Lockheed Martin) was successful, serious, ethical, and caring. Of those ten indicators of successful persuasion, seven reached statistical significance. In the classroom setting at least, the Ethics Challenge performed admirably.


Recent and Related Studies

This study addressed an ongoing controversy about the effectiveness of humor in persuasion. Practitioners insist that it is effective, but researchers are rarely able to find its effects. The current study tried to find and identify those effects using theoretically grounded predictions, a carefully controlled environment, and sensitive (liberal) statistical measures. Small effects were found and explained in terms of persuasion theory.

Unlike earlier studies on this topic, constructs were specified as carefully and clearly as possible. Different types of humor were identified and dealt with separately. Predictions were grounded in established theory. The experiment was conducted in the quasi-field setting of a classroom rather than under sterile laboratory conditions. Tight controls on internal validity allowed the researcher to draw causal inferences. Statistical analysis was kept simple and reported responsibly to uncover subtle effects without inflating confidence in the results.

These precautions seem to have paid off. Although the results of the current study were small and tenuous, they were significant. Many recent studies have been unable to report significant results.

Great strides have been made recently in research on humor and laughter . Research on the use of humor in advertising has recently uncovered an interaction between the use of humor and argument strength . Another study documented a sleeper effect, when immediate recall was not improved by the use of humor but long-term recall was improved . Work in the area of persuasion and attitudes has tended to focus more on emotions in general than positive emotions .

It is usually agreed that participants in a positive mood are easier to persuade. However, Adam Zuckerman reported an unusual result. Using participants with high involvement in the issue under discussion, he found that those who were in a positive mood were more confident in resisting persuasive attempts .

Steven Michaels recently investigated the effectiveness of humor in persuasion in advertising. He found that the use of humor increased liking for the ad, and liking for the brand, but actually reduced recall and had no significant effect on persuasion . His conclusion was that humor could generate affective responses but inhibited cognitive ones, and thus could not reliably support persuasion.

In general, studies of the persuasive effect of using humor often lead to small and inconclusive results. This study has tried to correct for the situations that tend to produce these results.


The participants were young students. They probably took the whole experience as an academic exercise, and were less involved in it than workplace employees might have been. Because of the severely restricted age range, one cannot generalize the results beyond this age group.

The intense focus on internal validity (to enable causal inferences) came at the expense of external validity, threatening the ability to generalize the results to other situations. For example, in the name of consistency, the researcher personally led each administration of the experiment. This practice was successful, but also introduced the possibility of researcher bias, the effects of which are difficult (for the researcher) to identify.

This practice also failed to replicate the usual situation in which the Ethics Challenge is conducted. In the workplace, the Ethics Challenge is conducted a conference room where it is a complete break from employees' regular business activities. However, the current study was conducted in a classroom to which students were accustomed. Also, the Ethics Challenge is a small group activity, while the current study was conducted individually (to isolate the effects of humor on persuasion from the effects of humor on group dynamics).

Three of the adjectives selected for the descriptive-adjective rating turned out to have little value, and the post-test cases turned out to be more difficult for these participants than the pre-test cases. These errors limited the usefulness of the results.

The statistical analyses were very simple. Hypotheses were investigated with t-tests and interactions were sought with simple linear regression. More sophisticated techniques, such as LISREL, might have uncovered more interesting relationships among the variables. This study was limited by not only the poor definition of constructs in the field, but also the knowledge and experience of the lone researcher.

The hypotheses were tested with a very liberal statistical test. Without adopting a correction such as the Benjamani and Hochberg procedure for false discovery, this study may be rejecting null hypotheses on the basis of results that should only have been considered at an alpha level of .10.


Implications for Theory

Persuasion theory suggests that people are more amenable to persuasion when they are in a good mood. This may be because those in a good mood avoid central/systematic processing , because happy people are willing to rely on general knowledge structures instead of carefully analyzing arguments , or simply because peripheral/heuristic processing is the default mode for humans . Either way, it was expected that participants who were put into a good mood with humor would be more responsive to persuasion.

It was expected that cartoon drawings would put participants in such a mood, but that did not seem to occur in the current study. No surrogate measure for mood indicated any significant effect for cartoon drawings. Thus there is no support here for the contention that such illustrations are effective in making readers more malleable, or even that such mechanisms will increase liking for the source. Perhaps receivers have been desensitized to this sort of cute illustration, with the prevalence of PowerPoint and other clip art in teaching and public speaking. This experiment did not provide a test of the preferences of participants whose mood had been successfully elevated.

It was also thought that self-effacing humor would enhance source credibility and increase the persuasiveness of the message. While there was evidence to suggest that the self-effacing humor increased source credibility (agreement that the adjective serious was applicable to the sponsor), and while there was a clear effect on the persuasiveness of the message, it was not as strong an effect as expected. In particular, it has been argued that a very credible source is more effective than a well-liked source , but the credibility benefit of self-effacing humor did not seem to trump the strong persuasive effect of ironic wisecracks in the current study.

Correlation analysis revealed what may be an interesting challenge to our common sense notions about humor. In the contemporary politically correct environment, it is often assumed that anyone who laughs at a certain type of humor is agreeing with and condoning the positions advanced in the humor. If someone enjoys offensive humor, that person is suspect. However, the current study throws some doubt on that assumption.

In this study, there was only a two-thirds correlation between finding Dilbert funny and agreeing with Dilbert. Although that is a high correlation, it is by no means a one-to-one relationship. It seems that there were people who found Dilbert's antics amusing without reporting any agreement with his perspective. On the other hand, there were people who did not find his antics amusing, even though they agreed with his perspective. Perhaps it is not true that laughing at something (or finding it funny) really implies anything about our opinion on the matter.

Implications for Practice

Practitioners often want to use humor to support persuasive messages in the fields of education, advertising, and politics. In general, the results of the current study support the contention that humor can be used effectively for persuasion.

However, the results do not suggest that humor is inherently or automatically effective. For example, the discussion above challenged the notion that people who are laughing or smiling are necessarily buying into the message being advocated. Therefore it is not the finding of this study that humor always or even usually supports persuasion.

The specific application of humor that was used in the current study had several characteristics that may have been essential to its success.

The humor in this exercise was prepared ahead of time. Spontaneous joking sometimes does more to reveal a speaker's subconscious issues than to further the goals of an activity . The humor in this case was written, rather than verbal, and planned rather than spontaneous. There is nothing in the current study to suggest that off-handed remarks by a persuader would work as well, or would work at all.

The humor in this exercise was expertly prepared. Just as the mini-cases in the Ethics Challenge had been selected and revised carefully by ethics officers, the Dilbert humor was carefully reviewed and revised by Scott Adams himself . There is nothing in the current study to suggest that amateur humor would work as well, or would work at all.

The humor in this exercise was directly relevant to the subject matter. Remarks were made about the ethical situation in the mini-case, or about the multiple-choice answers. Gathering canned jokes of varying relevance to a topic can do more to distract participants than to guide them . There is nothing in the current study to suggest that less relevant humor would work as well, or would work at all.

It cannot be overemphasized that the results found in the current study were very small. Of a total of thirteen measures of the dependent variable (persuasion), only three reached significance. Expectations and promises for the use of humor should be carefully limited to those that are realistic.

A humorous intervention may be like a spice. It can be used to enhance, but not replace, the essential ingredients. The humor in the Ethics Challenge was used to support a persuasive message that was reasonably effective even without the humor. There is nothing in the current study to suggest that the use of humor would bolster a weak persuasive message.

Furthermore, whenever the effectiveness of a humorous intervention is in doubt, its ability to offend can offset its benefits and make it advisable to exercise restraint.

The powerful impact of using irony must always be weighed against the possibility of generating offense. In the current study, the use of ironic wisecracks did not seem to generate offense among the participants (as measured by their assessment of the sponsoring company). This may be because the distraction task of decoding irony prevented listeners from preparing counter-arguments, as theory suggests. On the other hand, it may simply be due to the current popularity of sarcasm as a comedic style. However, when the possibility of offense is an issue, self-effacing humor may be preferred in spite of its slightly poorer showing in this study.

The current study only supports the contention that professionally produced humor, pre-arranged in written form, and directly relevant to an effective persuasive message can create small effects in support of that persuasive message.

Implications for Research

Because the approach taken in this experiment was successful in generating analyzable results, it will probably be retained for future studies. In particular, within-subject gain scores (post-test minus pre-test) proved to be quite sensitive to the small effects expected in such cases.

However, the descriptive-adjectives, which had been developed during an earlier pilot study, were not very productive. It might have been preferable to have adopted a set of generic adjectives used in previous descriptive-adjective rating activities.

The pre-post-test control group design that was used seemed to work well for this group, which consisted of students. They were accustomed to written tests and there was no reason to suspect any unintended effects due to pre-testing . With non-student participants (such as workplace employees), pre-testing might have a different effect. In that case, it might be wiser to adopt a Solomon design. Even though it requires recruiting more participants, repeating all the humor treatments with and without a pre-test (as required by the Solomon design) would identify any effects attributable to pre-testing of the participants.

The separation of the humor elements revealed the differential effects of each type of humor. This separation provided useful information and it should probably be repeated in future studies. Because humor is usually made up of complex stimuli, there are opportunities to break them into their constituent parts (when they are able to stand on their own) and assess the effects of those independent parts.

The current study was carefully controlled to protect internal validity. The humor in each administration of the experiment was identical, because it was written and did not rely on delivery. The investigator was identical for each administration, since the researcher led all the sessions himself and dutifully followed a topical outline. All of these controls ensured that valid causal inferences could be drawn from the study.

However, these same controls also threatened external validity. The tight controls of the classroom setting limited the ability to generalize these findings to a workplace. The use of the researcher as primary investigator may have introduced subtle experimental biases which are difficult (for the experimenter) to recognize. In order to be able to get transferable knowledge in future studies, a better balance of these goals should be sought.

The propositions and hypotheses of this study were developed through widely accepted persuasion theory. Since humor research lacks a reputation for rigor, the use of accepted theory from outside the field is recommended. In this study, the use of persuasion theory made the results easier to interpret. In general, it would probably improve the credibility and significance of most humor studies to adopt accepted theory from outside of the field of humor research.

However, this argument is not meant to advocate research in which humor is merely used as an indicator of some underlying phenomenon (e.g., ethnic jokes as indicators of multiculturalism). Instead, this argument is meant to advocate bringing in established theories to add credibility and legitimacy to investigations that take humor as the phenomenon of interest.


Following Up on This Study

This experiment should be replicated with older and more experienced participants, who are representative of the intended audience for the Ethics Challenge. This group could consist of older students (such as part-time MBA students), but ideally would be made up of employees in a workplace similar to that of the Lockheed Martin companies. These participants would be more directly involved in the issues that are addressed in the mini-cases. According to the elaboration likelihood model, they would therefore be more likely to focus on central (systematic) arguments than peripheral (heuristic) cues, and would thus be more resistant to the use of humor to enhance persuasion. This would provide a more severe test of the effectiveness of the humor in the Ethics Challenge.

In future research, the Ethics Challenge should be used in its intact form. The group-level effects of the humor should be assessed by a co-investigator with the background and interest to make such observations. Because the current study is a doctoral dissertation, it had to represent the individual effort of the author.

In several places in the current study, explanations have been offered for the effects observed. These should be tested directly. For example, it has been proposed that cartoon drawings failed to support persuasion significantly because they failed to create a good mood. That mood could be assessed more directly using an instrument such as a mood adjective check list . It was also suggested that ironic wisecracks might operate as a distraction task, inhibiting the generation of counter-arguments. This contention could probably be assessed directly using methods unknown by this researcher.

Theory and Nature of Humor

The field of humor research presents many interesting opportunities for new scholarship. Almost every aspect of the field is open to question. Even humor's definition is uncertain.

There are many theories of humor, none of which is wholly satisfactory. Many deserve empirical investigation. Several of them have convergent validity, but lack divergent validity. For example, incongruity theories suggest that humorous events involve some sort of incongruity, which seems to be true. However, incongruity theories cannot explain why some incongruous events are not funny.

Existing theories can explain some instances of humor, but no theory has been developed that can explain all instances of humor. For this reason, some researchers have concluded that there may be no essential thing that all instances of humor share in common. They feel that the word humor is just an umbrella term for several related phenomena that bear a family resemblance, in the Wittgensteinian sense.

No such essence has yet been found, and it is unlikely that it will be found soon or easily. However, this researcher is not yet ready to concede that there is no essence of humor. It seems that, at the very least, different instances of humor may share some important phenomenology within receivers.

Organizing the Researchers

The recent revival of scientific interest in humor is only about three decades old. That revival has been subtle, with perhaps a thousand researchers across the world working on diverse aspects of humor and/or laughter. About 300 of them are allied through the International Society for Humor Studies. This association holds annual scholarly conferences and has produced the academic journal Humor: International Journal of Humor Research since 1988. It is published by Kluwer and indexed by PsycInfo ABI/Inform, and other academic on-line services.

In spite of the work of this venerable agency, research into humor has not been well funded. It is usually conducted by university professors who squeeze the work in between teaching and other responsibilities. They are from a variety of disciplines, but have in common that most of them are fully tenured. Few tenure-seeking professors can afford to spend time on basic research (such as defining or characterizing humor), since the work is slow and methodical and leads to few publications. New professors must spend their time instead generating research that will result in several early publications.

The one thing that would move this research forward is an injection of financial support. The availability of funding would encourage researchers from various disciplines to indulge their interest in humor and laughter. The source of such funding should probably be famous comedians, who have become wealthy through the use of humor. They could perhaps be prevailed upon to establish named institutes for research into humor.

Immediate Activities

Some of the work that has been done in the area of humor studies has been premature. It may have to be repeated when we arrive at a proper definition of humor and the constructs involved in a workable theory of humor. Work in such areas should perhaps be deferred.

However, there are some research streams that can proceed even without resolving such basic issues. For example, the effectiveness of humor in advertising, training, and motivation can be assessed using widely accepted instances of humor.

Any humor research that is undertaken should be done carefully and skillfully to establish a legitimate reputation. Symposia should be mounted at major academic conferences and studies should be conducted according to the rigorous standards of major journals.

Furthermore, it is the responsibility of humor researchers to educate consumers about the optimistic claims of consultants, health providers, and other self-interested parties. Such claims should be investigated and realistic expectations should be engendered by humor researchers.


In the last three decades there has been a renaissance of scientific interest in the phenomenon of humor. When it comes to humor in persuasion, especially in advertising, there has been a significant volume of research. The elaboration likelihood model has been brought to bear on receiver characteristics such as individual differences in involvement and need for cognition.

However, the classic work on the effectiveness of humor in persuasion is still that of Dorothy Markiewicz. She found that participants' mood was elevated by the use of humor, but that the effectiveness of a humorous message had more to do with participants' initial opinions on the matter. She concluded that humor did not influence persuasion significantly, that humor's effects on comprehension and source evaluation were inconsistent, and that retention did not appear to be altered by humor usage.

She also pointed out severe methodological problems with prior research including inadequate control messages, questionable humor manipulations, inappropriate settings for receipt of humor, limited participant populations, and blatant demand characteristics. She advocated considering learning theory or distraction effects in future research and looking more closely at humor's effects on source credibility .

The current study responded to these concerns. It used tight controls to assure that any differences in the dependent variable were attributable to the humor manipulation. It adopted the accepted and proven humor of Scott Adams' Dilbert characters. The experiment was conducted in a quasi-field setting, and the intent was disguised to thwart demand characteristics. Participants' initial opinions were taken into account with pre-test measures of the variables, and there was a focus on both the distraction effects of irony and the credibility enhancement of self-effacing humor.

The results of the current study confirmed that humor can support persuasion. It is reasonable to assert that humor can support a persuasive message, even when the topic is as serious as business ethics.

However, the results obtained here also suggest some caveats that may help to explain why humor's effects are elusive in well-controlled experiments.

First, the effects are very small. It is misguided to contend or promise that the use of humor will generate impressive results, or that it will provide anything more than a marginal improvement in the strength of a persuasive message.

Second, the effects do not seem to be attributable to humor making people feel better. While it is common knowledge that the use of humor makes us feel good, that good feeling may not increase persuasive effectiveness. Accordingly, it is misguided to assess humor in this context on the basis of whether people like it, or whether it makes them feel good.

As suspected by Markiewicz, the effects seem to be more attributable to the distraction effects of humor and its ability to enhance source credibility. When selecting humor for inclusion in such an appeal, it is more important to assess whether it provides sufficient mental challenge to serve as a distraction and whether it enhances source credibility than whether it makes viewers feel happy.

© 2001, James Bruce Lyttle