> Ancient societies ... were much more careful when introducing new technologies

I do not believe this for a minute.

> But I think they would be more surprised by how we managed to invent things ... which destroy our brain.

what kind of destroy are you talking about?

modern living changes brain development, it doesn't destroy things -- the brain is an ever-molding plastic object for that very reason, situations change and require different access to different things; unless by destroy you want to talk only of neuron number ; jury's out on that.

'Ancient societies' , let's talk Greek since you brought up Plato, ate and drank lead -- both accidentally and on purpose. destroyed their teeth on rock grit from stone mills and had zero ability to deal with the resulting abscesses aside from brutal surgeries without anesthetic, sterilization or antibiotics , inhaled burning wood smoke indoors just about everywhere, believed that the majority of natural happenings were omens , believed the womb caused women to 'wander', requiring infantilization and control of anyone with one, trained their militarizes through starvation and beating and rape/pederasty relationships were common place and even legally bound.

so, actually I think that ancient societies would be more surprised by the fact that nearly every one of their ritualistic ways of dealing with the problems that arose in their life was either 1) ineffective, 2) harmful, 3) deadly.

but first you'll have to convince them of what their brain even does ..