In the United States (at least), when somebody sneezes, it is very common to hear another person say, "Bless you." Even strangers frequently will respond to a sneeze with, "Bless you." Originally, a sneeze was thought to make one vulnerable to evil spirits. Therefore, people would say, "Bless you" in order to counteract that. But how is this a meme (a replicator of culture)?
There had to be a first instance of "Bless you." When that occurred, other people heard it said, and perhaps questioned why it was said. For whatever reason, they were convinced that it was a good idea to continue saying it when people sneezed. And that habit has continued to this day, even though the meaning now has mostly been lost—people basically do it out of courtesy and habit. Regardless, is this a meme? Let's look at the primary characteristics of a replicator:
- Copying Fidelity: Clearly the behavior of saying, "Bless you" has been copied by people through generations, unchanged in essence.
- Selection: Other things may have been said or done after a sneeze, but those behaviors, if they existed, have not carried down to us. However, the saying of "Bless you" has been selected as a behavior to be imitated.
- Variation: The behavior has continued unchanged in essence through generations, but small variations have occurred. For instance, this behavior likely started as, "God bless you," from which has evolved the shorter variation, "Bless you." Also, "gesundheit" is a very common variation as well, which is German for "health." Technically, gesundheit might not be considered a variation, given that it conveys the same concept as "Bless you," just in another language. But the fact that native English speakers, who know no German, use "gesundheit" in place of "Bless you" indicates that it has been adopted (imitated) for the same purpose. Hence, I think we can classify it as a variation.
- Fidelity: As I noted above, the essence of the behavior has carried down nearly unchanged, which means that this behavior's copying fidelity is quite high.
- Fecundity: This behavior can replicate quite quickly. One might be exposed to the behavior every time a person nearby sneezes or, more strongly, every time one sneezes. Even if one did not learn such behavior when young, one can easily imitate it through frequent exposure throughout life.
- Longevity: This behavior is simple to perform and is courteous; thus, there will be little aversion to performing it. Hence it has an innate leaning toward longevity.