I still
question your assertion that knowledge of what is safe and what is not is
hard
wired into us.

let me clarify what is hard wired is the means of discovering if a food  is
good or bad to eat . what is hard wired is the connection between metabolic
needs and sense of smell and taste that makes a food tastes good when needed
and bad tasting or uninteresting when not needed


<and  We
have the longest childhood of any species on the planet, by far. One of the
consequences of
that is that we must be taught things which are actually not hard wired into
us anymore.>

the learning experince of childhood is there to exercise our instincts , to
fine tune the details of what our instincts lead us to do .

 I'm not
saying we don't have instincts anymore, but children who put objects into
their mouths at the
stage of development you are describing will put any object into their
mouths
whether they are
hungry or not, whether it is good for them or not, whether it is edible or
not. This is a well
known-stage of child development and is not about food.

it is not "not about food "either . at this stage of developement the mouth
is a means to explore the world to get information about it in texture smell
taste .... that include foods,  especially because any species have to learn
the way to balance their inner ecology in relationship to the outer ecology

 what i observed is that an infant that get plenty of natural foods to
experience don't need to put so much inedible  things in their mouth , my
chidren did very little of that while i saw their friends looking for
something desesperatelly

.they never spit out foods either,  something considered normal at this age
, because they will not put something in their mouth that din't pass the
test of attractive  smell first .( and they have never been forced either )

jean-claude