The deterioration of mental health of our population is usually interpreted as the result of the increased modern life stress in our atomic age with its implications of the « cold war ». It is not a greater cultural life stress, however, but rather a lower individual resistance to it that accounts for the increased frequency of psychoneuroses in modern society. The term « mental retardation » comprises two categories: one is caused by genetic factors or acquired intra-and extrauterine diseases of infancy and childhood, the second is due to functional mental retardation if the normal individual genetic endowment has not developed to its full capacity and has persisted in a state of immaturity without any interference of a disease. The characteristics of such functional mental retardation (psychic infantilism) and their manifestation in society are outlined in detail. Instincts and emotions insufficiently inhibited by intellect determine the behavior of the functionally mentally retarded. Deficient ethics and responsibility are very often consequences of deficient intellect. Conformism is a subterfuge and evasion from personal responsibility. Exuberant imagination and fantasy of an immature mind, uncontroled by intellect, becoming prevalent in a schizoid personality have eliminated the concept of beauty-and this is the essence of aesthetics-from creative art, music and literature. Mental hygiene is chiefly the job of the family home and the teachers in primary and secondary schools. Education is more than drill and training. Teachers cannot be replaced by machines. Automation technics, recently used even for personality assessment, are out of place in this field.