In H. sapiens this has less to do with speciation and more to do with economic drivers. That is, we adapt to societal circumstance more than other species do. E

In H. sapiens this has less to do with speciation and more to do with economic drivers. That is, we adapt to societal circumstance more than other species do. Examining populations in the 18th century, you needed to have a higher number of children, because half of them were likely to not make it to adulthood. In modern Western society, this is no longer true, but that's a new wrinkle that has arrived in the last fifty years. That family behaviors didn't change to a noticeable degree until roughly twenty years ago, tells you there's something more going on than "the species is just like that."