A taboo is a societal prohibition on an action or topic of discussion. Any attempt to discuss the idea or take the action is met with severe social opprobrium, shunning, and often even worse consequences.

Some taboos are automatic - people shun the action or idea instinctively. Other taboos are cultural - a group of people have abhorred the practice for so long that the response is ingrained throughout society. But some taboos come into existence more rapidly than that. People push taboos to enforce their morals, or preferred practices.

Sometimes taboos fade over time - homosexuality was once taboo in American cultural, both in terms of the action and the discussion of the topic. Now, it has ceased to be taboo, even among people who are not in favor.

Social media can interact with taboos in novel ways: There is more opportunity for people who would like to enforce a taboo to learn of people violating that taboo, and more opportunity for that enforcement to gain support. However, such viral processes are necessarily scattershot: Only a small fraction of statements will grow to enough prominence for a taboo to be enforced.

This week, we’re going to discuss taboos as a mechanism of spreading moral values. On the one hand, a taboo presents severe negative consequences to the discussion of an action that one believes to be immoral. It makes it clear to anyone who is wavering that the behavior is NOT OK. This can cause people to avoid discussing or even considering the idea. This is especially true when the taboo is close to universal in a discourse group. On the other hand, a taboo does nothing to convince people that the idea is wrong, merely that it is out of favor. Moreover, a taboo is only effective in social circles where the taboo is being enforced, and can drive borderline people into more accepting and encouraging circles, potentially increasing the behavior under taboo.

When should taboos be used to try to spread moral values? When the belief is already nearly universal? When the belief is still emerging? In a setting where a taboo exists, how should one navigate the situation? If one agrees with the moral position? Disagrees? Is uncertain?