Here is one way to approach the problem:
I assert that nearly every sane person is already a utilitarian with respect to his or her self. This is easy to see by observing what people do and do not do. What is preferable: to push a pencil through your eye or to eat breakfast? The answer is easy for every sane adult because every sane adult can understand the outcome and make a decision based on the outcome.
Where do people falter when applying utilitarianism more globally: when the beneficiary is somebody else or the benefit to the self requires consideration of a complex chain of events (like the side effects of setting a good example for others or following norms that reflect a preferred social system that benefits all).
There might be ways to appeal to existing instincts as a mean to pursue behavior change. There is a field of study on attitude change, and it is used, for better or worse, by people who want to sell you something, people who want to convert you to their religion or philosophy, people who want to reduce health-risk behaviors, and so on. You can search the Internet or a university library for 'attitude change.' You can start here:
Wikipedia. If you have never studied social psychology and are interested, there is an iTunes University course for 'Sociology 150a' as
audio and as
video (video is on iTunes too).
Efforts to change beliefs or behaviors might need to be targeted to the beliefs or behaviors that are antecedent to the desired outcome (in other words, address some fundamental beliefs that that need to be fixed so that people get the 'right' answer on the higher-level problem). Some ideas:
* Get people to take the perspective of others (this is called 'perspective-taking' and has been studied extensively),
* Get people to appreciate the value of considering future outcomes (there are studies of how people vary in their consideration of consequences but I'm not sure of any attitude-change procedure for it. One measure is called the 'Consideration of Future Consequences Scale' that has been correlated with various pro-social and pro-environmental behaviors).
* Identify a norm that most people follow, then emphasize its importance. One norm is to simply consider others. No sane person pisses on the floor in the grocery store because we are considerate of others (or that is at least the reasoning that could be claimed as the norm). The tactic of explaining what people typically do has been used to reduce alcohol consumption in universities, and I have seen billboards near me using the tactic to get people to stop chewing tobacco.
** another norm might be to emphasize the importance of cognitive consistency---some people simply do not care that they hold beliefs that are contradictory, and the simply avoid scrutinizing their beliefs. They often experience a version of
Moore's paradox in which they might have no rebuttle to a rational argument against their belief, but they maintain that belief because they think that there must be a flaw in the rational argument even though they cannot find it.
** another norm to support with attitude change might be that people recognize the need to study ways to identify truth (counteracting the idea of self-evident truths). Nobody builds an airplane without study or does any scientific work without study, yet people believe that their gut feelings can provide them with answers on complex problems like understanding the social consequences of one's actions. People have a strong tendency to believe that they understand truth when in fact they do not (sometimes leading to religious or political wars). People are often unaware of the origins of their own behavior because the processes that control that behavior are unconscious (
Johnson et al.); they have illusions of insight, illusions of external agency, illusions of control, they are unaware of the nature of their prejudices, and so forth. Understanding this is impeded by a 'feeling of knowing' that is not anchored to actual knowing. At the very least, a sense of epistemological humility might help---getting people to consider that their beliefs are only tentative and not 100% factual.
anyway, those are some ideas.