Fromm, E.
(1973).
The Anatomy of Human Destructiveness.
"On the other hand, the psychic pain can be as intense or even more so than the physical. I do not need to give examples for this mental sadism. Parents inflict it on their children, professors on their students, superiors on their inferiors—in other words, it is employed in any situation where there is someone who cannot defend himself against the sadist. (If the teacher is helpless, the students often turn into sadists.) Mental sadism may be disguised in many seemingly harmless ways: a question, a smile, a confusing remark. Who does not know an 'artist' in this kind of sadism, the one who finds just the right word or the right gesture to embarass or humiliate another in this innocent way. Naturally, this kind of sadism is often all the more effective if the humiliation is inflicted in front of others." (p. 318)