While Lombroso researched the purported physiological factors that motivated criminals, Ferri investigated social and economic aspects.

Ferri was born in Lombardy, then part of the Austrian Empire in 1856,[1] and worked as a lecturer first and later as a professor of Criminal law, having spent time as a student of Cesare Lombroso.

These characteristics included slang, handwriting, secret symbols, literature, and art, as well as moral insensibility and "a lack of repugnance to the idea and execution of the offence, previous to its commission, and the absence of remorse after committing it".

Ferri argued that other sentiments, such as hate, cupidity, and vanity had greater influences as they held more control over a person's moral sense.

[2] Ferri often drew comparisons between socialism and Darwinism, and disputed particular works by Ernst Haeckel that highlighted contradictions between the two schools of thought.

Ferri observed that as Darwinism dealt a damaging blow to religion and the origins of the universe according to the church, so socialism rose in comparison.