Shared interests of unrelated symbionts

Unrelated symbionts tend to affect the host in similar ways. For example, many symbionts tend to make hosts leak bodily fluids - through bleeding, diarrhea, coughing, sneezing and pimples. Similarly, many stimulate interactions between hosts to facilitate their own reproduction - with rabies, toxoplasmosis and malaria being some of the best-known examples.

Can we make the same sorts of statements about cultural symbionts? I think so. Most of the rest of this post will give examples. Speaking and writing skill skills are a common pathway into the future for many memes. Speaking to large audiences is especially desirable. Teaching skills are particularly useful to many memes.

Like their organic counterparts, cultural creatures depend on contact between their hosts for their transmission - and so many of them tend to promote frequent, peaceful host interactions.

Another area involves resource allocation. As with organic parasites, many cultural parasites benefit from reducing the fertility of their hosts. Resources spent on host reproduction are resources not available for parasite reproduction. There's a considerable body of evidence that shows that memes do tend to have this effect.

Symbionts are also interested in host lifespan. They tend to follow one of two strategies. One involves turning the knob that controls the reproduction-maintenance axis towards maintenance - a living host is typically more useful to symbionts than host offspring are. This tends to increase host lifespan. The other strategy is to burn through host resources and convert them into symbiont offspring as fast as possible. Ebola would be an example of this strategy. This sort of thing tends to decrease host lifespan. The second strategy is often especially harmful to the host.

The whole phenomenon of shared symbiont interests is, I think, something useful to be aware of. If many agents are attempting to influence you in the same direction, that increases the chances of their collective manipulations being successful. Some people might want to take steps to compensate.