There is scarcely room for doubt that something in the psychological relation of a mother-in-law to a son-in-law breeds hostility between them and makes it hard for them to live together. But the fact that in civilized societies mothers-in-law are such a favourite subject for jokes seems to me to suggest that the emotional relation involved includes sharply contrasted components. I believe, that is, that this relation is in fact an 'ambivalent' one, composed of conflicting affectionate and hostile impulses.