"Based on decades of compelling data (including the latest DNA analyses), many researchers, myself included, think that the g-factor is influenced mostly by gen

"Based on decades of compelling data (including the latest DNA analyses), many researchers, myself included, think that the g-factor is influenced mostly by genetics." -- Can anyone here tell me the canonical way of excluding environmental factors in intelligence research? How can a neural network learn its weights without proper data? What I can imagine though is genetics heavily influencing your behavioural patterns creating an environment that in turn impacts your g-factor. "Since the first neuroimaging studies of intelligence, researchers have been trying to predict intelligence test scores from images. […] It was based on a mathematical way to assess how brain areas were connected to each other using MRI scans. Apparently, such connection patterns are stable and unique to individuals like fingerprints; and these patterns predict intelligence test scores." -- Is he talking about white matter? Doesn't it increase in volume long into adolescence?