I don't understand this either. Perhaps one has to look further into the details of the model. (My general fear with these models is that they are so abstract

I don't understand this either. Perhaps one has to look further into the details of the model. (My general fear with these models is that they are so abstracted from reality, that by tweaking parameters or assumptions you can find anything.) > She also speculates that interspecies transmission of microbes — from dogs to humans, say, or the other way around — could affect interspecies altruism, another prediction that could be tested using animal models. This reminds me of the speculation that index funds hurt competition between firms. (In brief: Nowadays, every investor owns both United and Delta; so why would the investors want them to compete with each other?) The microbial species is the investor. https://www.bloomberg.com/view/articles/2015-07-22/index-funds-may-work-a-little-too-well https://www.bloomberg.com/view/articles/2015-07-22/index-fun...