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The results of two experiments examining infants at 6, 9, 12, 15, 18, and 21 months of age and varying levels of father interaction are summarized to show that separation protest is more a function of a strange person remaining in an unfamiliar laboratory situation with the infant than the temporary loss of a specific parent. The use of protest as an index of infant-parent attachment seems undesirable.
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Kotelchuck et al. (1975) studied this question.
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