As an American, Banfield was witnessing what was to become infamous as the Southern Italian Mafias and a self-centered clan-system promoting the well-being of their inner group at the expense of the other ones.

Banfield postulated that the backwardness of such a society could be explained "largely but not entirely" by "the inability of the villagers to act together for their common good or, indeed, for any end transcending the immediate, material interest of the nuclear family.

"[1] Banfield concluded that Montegrano's plight was rooted in the distrust, envy, and suspicion displayed by its inhabitants' relations with one another.

However, for various reasons, historical and cultural, they did not have what he termed "social capital", the habits, norms, attitudes, and networks to motivate people to work for the common good.

This, he argued, was probably created by the combination of certain land-tenure conditions, a high mortality rate, and the absence of other community building institutions.