Seven hundred years ago, Frederick II, Holy Roman Emperor, conducted an experiment to determine what language children would grow up to speak if they had never heard a single spoken word. Would they speak Hebrew-then thought to be the bl dest tongues-or Greek or Latin, or he language of their parents? He instructed foster mothers and nurses to feed and bathe the children but under no circumstances to speak or prattle to them. The experiment failed, for every one of the children died. Class Can field, undated promotional letter, Planned Parenthood Federation Whether this anecdote is historically true is not known, but it does point attention to social experience as a.necessity for human growth. Personality development snot simply an automatic unfolding of inborn potentials, as is shown by social isolates. Several times each year the newspapers report instances of neglected children who have been chained or locked away from the normal family group. They are always found to be retarded and generally antisocial or unsocial.
Without group experience human personality does not develop. The most dramatic reports are those of so-called feral children, separated from their families and supposedly raised by animals [Singh and Zingg, 1942; Krout, 1942, pp. 106-114]. Social scientists doubt that a child would live for long in the care of animals. They suspect that so-called feral children are simply socially isolated and neglected children who had been either lost or abandoned by their parents and then discovered by others some time thereafter Burnout, 1959}
It is doubtful that allegedly feral children are examples of animal nurture. It does seem evident, however, that children who suffer
extreme emotional rejection and are severely deprived of normal loving care fail to develop the personality we usually consider human. This conclusion is consistent with the findings of a number of experiments in which animals which normally live in groups were raised in isolation. from their normal groups. Harlow and Harlow,  raised monkeys in isolation from all contact with other monkeys with only a heated terry-cloth-covered wire framework as a substitute “mother,” from which they received their bottle and to which they received there bottles and to which not human beings, and we should be careful about drawing inferences from behavior par’ allele. But it i§ interesting to note that Harlow’s account of the effects of maternal deprivation in monkeys correspond so closely with observations of the effects of maternal deprivation in ham is Spitz, 1965]. It appears that both monkeys and humans need intimate group experience if ‘bey are to develop into normal adults.