I've encountered a number of articles and podcasts that extend the thesis that the process of domestication produces neoteny - that dogs are what wolf puppies would be if they never attained adult wolfhood. Many left the reader/listener with the idea that perhaps humanity had domesticated itself; purposefully weeded out those who become aggressive and self-involved and less trusting (by prison, execution, exile, cultural norms of fitting partners for reproduction) and made conditions more favorable for those who remain childish and collaborative longer. Hardly reproducible, but fun to think about.