Why cry? Adaptive significance of intensive crying in human infants

Author(s): Vuorisalo, T., Barr, R. G., Lehtonen, L.

Journal/Book: Evol Hum Behav. 1998; 19: 655 Avenue of the Americas, New York, NY 10010. Elsevier Science Inc. 193-202.

Abstract: Prolonged crying at the beginning of life in humans appears to be related to a specific stage of development, We address the possibility that the human infant's predisposition to increased crying might be adaptive in an evolutionary sense by promoting survival and future reproductive success of the child. We emphasize the evolutionary history of humans to derive four hypotheses about the benefits of intensive infant crying. First, according to an historical hypothesis, crying indicates distress of infants due to physical separation from their parents. In the evolutionary past of Homo sapiens, infants appear to have been continuously carried by their mothers. In those circumstances, prolonged physical separation probably meant abandonment by the parent, Second, crying may be an adaptation to decrease the likelihood of infanticide that has been common in many human societies during adverse ecological conditions. Assuming that the quality of offspring affects the probability of infanticide, intensive crying could enhance an infant's survival by signaling the vigor of the infant, The third hypothesis is that the infant may utilize his or her crying capacity to psychologically ''manipulate'' the parents to provide more parental care, Finally, the ''superchild'' hypothesis posits that crying may be a manipulation that attempts to avoid the costs of sibling competition by increasing the interval between births. Predictions that follow from each hypothesis are discussed.

Note: Article Lummaa V, Univ Turku, Dept Biol, Sect Ecol, Turku 20014, FINLAND

Keyword(s): colic; crying; infanticide; honest signaling; natural selection; parent-offspring conflict; survival; PARENT-OFFSPRING CONFLICT; BEHAVIOR

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