Substratum

At this stage a new civilisation, with its institutions, its beliefs,
and its arts, may be born. In pursuit of its ideal, the race will
acquire in succession the qualities necessary to give it splendour,
vigour, and grandeur. At times no doubt it will still be a crowd,
but henceforth, beneath the mobile and changing characteristics
of crowds, is found a solid substratum, the genius of the race(fucking erase this word, "UNCONSCIOUS ENVIRONMENTAL FACTORS" is the right one)
which confines within narrow limits the transformations of a
nation and overrules the play of chance. - Le Bon

One of the biggest examples of this substratum,

http://www.livescience.com/culture/090309-brain-religion.html

One question that remains unanswered is whether religion evolved as a central functional preoccupation for human brains in early societies, or whether it simply relied on brain regions which had evolved for other types of thought-processing.

Future research may also try to see if human brains respond similarly for different religions, given that this study focused only on Western Christian beliefs.

"The more interesting studies will wind up comparing different belief systems with similar dimensions to see if they also activate the same brain areas," Grafman said. "If they do, we can better define why those brain areas evolved in humans."

It probably started as our ancestors began recognizing their own existence, then they began questioning why they were here on this earth, which led them to realize that they were absolutely nothing and completely meaningless, helpless beings. This very truth hurt them and depressed them and since they didn't want their children(posterity) to feel as unspecial and meaningless as they felt, they fed them lies of their delusional significance. And the children(YOU!) grew up believing in those lies with a passion constantly activating certain parts of their brain that have been evolved and is still evolving.

So that's it. I'm done with Le Bon, finally.