Beginnings have been made in child study, psychiatry, and psychoanalysis of the effects of different types of isolation upon personal development. Some attention has been given to the study of effects upon mentality and personality of physical defects such as deaf-mutism and blindness. Students of the so-called "morally defective child," that is the child who appears deficient in emotional and sympathetic responses, suggest as a partial explanation the absence in infancy and early childhood of intimate and sympathetic contacts with the mother. An investigation not yet made but of decisive bearing upon this point will be a comparative study of children brought up in families with those reared in institutions. Psychiatry and psychoanalysis in probing mental life and personality have related certain mental and social abnormalities to isolation from social contact. Studies of paranoia and of egocentric personalities have resulted in the discovery of the only or favorite child complex. The exclusion of the boy or girl in the one-child family from the give and take of democratic relations with brothers and sisters results, according to the theory advanced, in a psychopathic personality of the self-centered type. A contributing cause of homosexuality, it is said by psychoanalysts, is the isolation during childhood from usual association with individuals of the same sex. Research in dementia praecox discloses a symptom and probably a cause of this mental malady to be the withdrawal of the individual from normal social contacts and the substitution of an imaginary for a real world of persons and events. Dementia praecox has been related by one psychoanalyst to the "shut-in" type of personality. The literature on the subject of privacy in its relation to personal development is fragmentary but highly promising for future research. The study of the introspective type of personality suggests that self-analysis is the counterpart of the inhibition of immediate and impulsive self-expression in social relations. Materials for an understanding of the relation of retirement and privacy to the aesthetic, moral, and creative life of the person may be found in the lives of hermits, inventors, and religious leaders; in the studies of seclusion, prayer, and meditation; and in research upon taboo, prestige, and attitudes of superiority and inferiority. BIBLIOGRAPHY: MATERIALS FOR THE STUDY OF ISOLATION I. CHARACTERISTIC SENTIMENTS AND ATTITUDES OF THE ISOLATED PERSON (1) Zimmermann, Johann G. _Solitude._ Or the effects of occasional retirement on the mind, the heart, general society. Translated from the German. London, 1827. (2) Canat, René. _Une forme du mal du siècle._ Du sentiment de la solitude morale chez les romantiques et les parnassiens. Paris, 1904. (3) Goltz, E. von der. _Das Gebet in der aeltesten Christenheit._ Leipzig, 1901. (4) Strong, Anna L. _A Consideration of Prayer from the Standpoint of Social Psychology._ Chicago, 1908.