Agreed. I'd say, a big part of what makes smarter people smarter is encountering more varied problems and environmental conditions that allow more kinds of prun

Agreed. I'd say, a big part of what makes smarter people smarter is encountering more varied problems and environmental conditions that allow more kinds of pruning in more areas. Wild horses are far smarter than domestic ones, for example. Your comment fits with my citation of a cavity-IQ correlation, here.