The Twenty-Second Prasad
It was around the time of ultimate control occurring with agrarian and sedentary-accumulating-conforming ways that non-care and death for newborns was common. Newborns were often and routinely abandoned, deprived, even killed.
Your species could not, of course, thrive during this period; and you would have died off if not for the fact that some of your humans were not as crazed as others and so carried out at least the minimal amount of care-giving for some newborns to reach maturity and themselves have offspring.
During this period, also, there were advantages for survival of newborns who had certain characteristics. Since newborns were increasingly seen as handicaps in the survival competition you created among yourselves, those that had traits fitting with the crazed perceptions of the fully growns were selected for survival increasingly.
So traits in helpless newborns that made them either seem less burdensome or more appealing were selected for and increasingly prevalent.
(to be continued)